Vulnerability-Lookup

GHSA-HC7P-6R8X-VR4Q

Vulnerability from github – Published: 2026-06-08 15:32 – Updated: 2026-06-09 15:32

Details

Improper neutralization of HTML-encoded characters in the URL validation function in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link.

Severity ?

5.4 (Medium)


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

8.5 (High)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-8833"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-08T13:16:33Z",
    "severity": "HIGH"
  },
  "details": "Improper neutralization of HTML-encoded characters in the URL validation function in Checkmk \u003c2.5.0p5, \u003c2.4.0p31, \u003c2.3.0p48, and all 2.2.0 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link.",
  "id": "GHSA-hc7p-6r8x-vr4q",
  "modified": "2026-06-09T15:32:08Z",
  "published": "2026-06-08T15:32:59Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-8833"
    },
    {
      "type": "WEB",
      "url": "https://checkmk.com/werk/20002"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/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"
    }
  ]
}

CVE-2026-8833 (GCVE-0-2026-8833)

Vulnerability from cvelistv5 – Published: 2026-06-08 12:06 – Updated: 2026-06-08 13:02

Title

XSS in urls

Summary

Severity ?

8.5 (High)


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

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Assigner

Checkmk

References

URL

Tags

https://checkmk.com/werk/20002

vendor-advisory

Impacted products

	Vendor	Product	Version
	Checkmk GmbH	Checkmk	Affected: 2.5.0 , < 2.5.0p5 (semver) Affected: 2.4.0 , < 2.4.0p31 (semver) Affected: 2.3.0 , < 2.3.0p48 (semver) Affected: 2.2.0 (semver)

Credits

Arvato Systems Offensive Security

Show details on NVD website

JSON

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  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-8833",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-08T13:02:39.672018Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-08T13:02:45.679Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Checkmk",
          "vendor": "Checkmk GmbH",
          "versions": [
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              "status": "affected",
              "version": "2.5.0",
              "versionType": "semver"
            },
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              "lessThan": "2.4.0p31",
              "status": "affected",
              "version": "2.4.0",
              "versionType": "semver"
            },
            {
              "lessThan": "2.3.0p48",
              "status": "affected",
              "version": "2.3.0",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "2.2.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "2.5.0p5",
                  "versionStartIncluding": "2.5.0",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "2.4.0p31",
                  "versionStartIncluding": "2.4.0",
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                },
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          "type": "reporter",
          "value": "Arvato Systems Offensive Security"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Improper neutralization of HTML-encoded characters in the URL validation function in Checkmk \u003c2.5.0p5, \u003c2.4.0p31, \u003c2.3.0p48, and all 2.2.0 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-63",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-63: Cross-Site Scripting (XSS)"
            }
          ]
        }
      ],
      "metrics": [
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          "cvssV4_0": {
            "baseScore": 8.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N",
            "version": "4.0"
          }
        }
      ],
      "problemTypes": [
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              "lang": "en",
              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-08T12:06:51.267Z",
        "orgId": "f7d6281c-4801-44ce-ace2-493291dedb0f",
        "shortName": "Checkmk"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://checkmk.com/werk/20002"
        }
      ],
      "title": "XSS in urls",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f7d6281c-4801-44ce-ace2-493291dedb0f",
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    "datePublished": "2026-06-08T12:06:51.267Z",
    "dateReserved": "2026-05-18T14:06:43.958Z",
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    "state": "PUBLISHED"
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}

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

GHSA-HC7P-6R8X-VR4Q

CVE-2026-8833 (GCVE-0-2026-8833)

Tags

Sightings

Nomenclature