Vulnerability-Lookup

CVE-2026-9256 (GCVE-0-2026-9256)

Vulnerability from cvelistv5 – Published: 2026-05-22 14:11 – Updated: 2026-06-30 12:10 X_F5

Title

NGINX ngx_http_rewrite_module vulnerability

Summary

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Severity ?

8.1 (High)


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

9.2 (Critical)


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

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

References

URL

Tags

https://my.f5.com/manage/s/article/K000161377

vendor-advisory

Impacted products

Vendor

Product

Version

NGINX Plus

Affected: 37.0 , < 37.0.1.1 (custom)
Affected: R36 , < R36 P5 (custom)
Affected: R32 , < R32 P7 (custom)

NGINX Open Source

Affected: 1.31.0 , < 1.31.1 (custom)
Affected: 1.30.0 , < 1.30.2 (custom)
Affected: 0.1.17 , ≤ 0.9.7 (custom)

Credits

"F5 acknowledges Mufeed VH of Winfunc Research, Nebula Security (@nebusecurity), and Vexera AI for bringing this issue to our attention and following the highest standards of coordinated disclosure."

Show details on NVD website

JSON

To clipboard

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      "cveMetadata": "{\"cveId\": \"CVE-2026-9256\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-06-30T03:15:43.184Z\", \"dateReserved\": \"2026-05-21T20:58:58.484Z\", \"assignerOrgId\": \"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab\", \"datePublished\": \"2026-05-22T14:11:41.877Z\", \"assignerShortName\": \"f5\"}",
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}

FKIE_CVE-2026-9256

Vulnerability from fkie_nvd - Published: 2026-05-22 15:16 - Updated: 2026-06-30 03:21

Severity ?

8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

References

URL	Tags
f5sirt@f5.com	https://my.f5.com/manage/s/article/K000161377	Mitigation, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108	http://www.openwall.com/lists/oss-security/2026/05/22/14	Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://lists.debian.org/debian-lts-announce/2026/06/msg00023.html
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:20351
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:28212
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:28921
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:28973
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:29151
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:29874
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:33313
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/security/cve/CVE-2026-9256
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://bugzilla.redhat.com/show_bug.cgi?id=2480746
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9256.json

Impacted products

Vendor	Product	Version
f5	nginx_open_source	*
f5	nginx_open_source	*
f5	nginx_open_source	1.31.0
f5	nginx_plus	*
f5	nginx_plus	*

JSON

To clipboard

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      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9256.json"
    }
  ],
  "sourceIdentifier": "f5sirt@f5.com",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "f5sirt@f5.com",
      "type": "Primary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
      "type": "Secondary"
    }
  ]
}

bit-nginx-2026-9256

Vulnerability from bitnami_vulndb

Published

2026-06-01 11:47

Modified

2026-06-22 06:07

Summary

NGINX ngx_http_rewrite_module vulnerability

Details

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "nginx",
        "purl": "pkg:bitnami/nginx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.1.17"
            },
            {
              "fixed": "1.24.0"
            },
            {
              "introduced": "1.30.0"
            },
            {
              "fixed": "1.30.2"
            },
            {
              "introduced": "1.31.0"
            },
            {
              "fixed": "1.31.1"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "type": "CVSS_V4"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-9256"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*"
    ],
    "severity": "Critical"
  },
  "details": "NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated.",
  "id": "BIT-nginx-2026-9256",
  "modified": "2026-06-22T06:07:36.958Z",
  "published": "2026-06-01T11:47:00.396Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/05/22/14"
    },
    {
      "type": "WEB",
      "url": "https://my.f5.com/manage/s/article/K000161377"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9256"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2026/06/msg00023.html"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "NGINX ngx_http_rewrite_module vulnerability"
}

CERTFR-2026-AVI-0643

Vulnerability from certfr_avis - Published: 2026-05-26 - Updated: 2026-05-26

Une vulnérabilité a été découverte dans Nginx. Elle permet à un attaquant de provoquer une exécution de code arbitraire à distance et un déni de service à distance.

Solutions

Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation).

L'éditeur indique que les versions 0.x de Nginx Open Source n'auront pas de correctifs

Impacted products

Vendor	Product	Description
F5	NGINX	NGINX Plus versions Rx antérieures à R36 P5 ou R32 P7
F5	NGINX	NGINX Plus versions 37.x antérieures à 37.0.1.1
F5	NGINX	NGINX Open Source versions postérieures à 1.31.0 antérieures à 1.31.1
F5	NGINX	NGINX Open Source versions 1.x antérieures à 1.30.2

References

Title

Publication Time

GHSA-H78R-86C6-JGP4

Vulnerability from github – Published: 2026-05-26 13:30 – Updated: 2026-06-30 03:36

Details

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Severity ?

8.1 (High)


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

9.2 (Critical)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-9256"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-122"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-22T15:16:27Z",
    "severity": "CRITICAL"
  },
  "details": "NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated.",
  "id": "GHSA-h78r-86c6-jgp4",
  "modified": "2026-06-30T03:36:47Z",
  "published": "2026-05-26T13:30:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9256"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:20351"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:28212"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:28921"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:28973"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:29151"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:29874"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:33313"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-9256"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480746"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2026/06/msg00023.html"
    },
    {
      "type": "WEB",
      "url": "https://my.f5.com/manage/s/article/K000161377"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9256.json"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/05/22/14"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

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

CVE-2026-9256 (GCVE-0-2026-9256)

FKIE_CVE-2026-9256

bit-nginx-2026-9256

Vulnerability from bitnami_vulndb

CERTFR-2026-AVI-0643

Solutions

GHSA-H78R-86C6-JGP4

Tags

Sightings

Nomenclature