ubuntu-cve-2025-46734
Vulnerability from osv_ubuntu
Published
2025-05-05 20:15
Modified
2026-04-27 14:25
Summary
Details

league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as html_input: 'strip' and allow_unsafe_links: false to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with on are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added href and src attributes now respect the existing allow_unsafe_links configuration option. If upgrading is not feasible, please consider disabling the AttributesExtension for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier.

Severity
6.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "php-league-commonmark",
            "binary_version": "1.3.1-1ubuntu2+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "php-league-commonmark",
        "purl": "pkg:deb/ubuntu/php-league-commonmark@1.3.1-1ubuntu2+esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.1-1ubuntu2+esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.1.2-1",
        "1.2.0-1",
        "1.3.0-1",
        "1.3.1-1",
        "1.3.1-1ubuntu2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "php-league-commonmark",
            "binary_version": "1.6.7-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "php-league-commonmark",
        "purl": "pkg:deb/ubuntu/php-league-commonmark@1.6.7-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.6.7-1ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.5.7-2build1",
        "1.6.6-1build1",
        "1.6.7-1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "php-league-commonmark",
            "binary_version": "2.4.2-2ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "php-league-commonmark",
        "purl": "pkg:deb/ubuntu/php-league-commonmark@2.4.2-2ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.4.2-2ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.3.9-1",
        "2.4.1-1",
        "2.4.2-1",
        "2.4.2-2"
      ]
    }
  ],
  "aliases": [],
  "details": "league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: \u0027strip\u0027` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier.",
  "id": "UBUNTU-CVE-2025-46734",
  "modified": "2026-04-27T14:25:50Z",
  "published": "2025-05-05T20:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2025-46734"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-46734"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/thephpleague/commonmark/commit/f0d626cf05ad3e99e6db26ebcb9091b6cd1cd89b"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/thephpleague/commonmark/security/advisories/GHSA-3527-qv2q-pfvx"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8194-1"
    }
  ],
  "related": [
    "USN-8194-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2025-46734"
  ]
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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