Vulnerability-Lookup

UBUNTU-CVE-2026-105829 (CVE-2026-105829)

Vulnerability from osv_ubuntu – Published: 2026-10-13 00:00 – Updated: 2026-10-13 00:00 – Source website

Details

League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone <script or <iframe line followed by a block supplying attributes like src or onload, executing stored scripts in viewers' browsers under default GFM settings.

Severity

6.1 (Medium)


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

5.3 (Medium)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-105829	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-105829	REPORT
	https://github.com/thephpleague/commonmark/securi…	REPORT
	https://www.vulncheck.com/advisories/league-commo…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "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"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.1.2-1",
        "1.2.0-1",
        "1.3.0-1",
        "1.3.1-1",
        "1.3.1-1ubuntu2",
        "1.3.1-1ubuntu2+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "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"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.5.7-2build1",
        "1.6.6-1build1",
        "1.6.7-1",
        "1.6.7-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "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"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.3.9-1",
        "2.4.1-1",
        "2.4.2-1",
        "2.4.2-2",
        "2.4.2-2ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "php-league-commonmark",
            "binary_version": "2.8.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "php-league-commonmark",
        "purl": "pkg:deb/ubuntu/php-league-commonmark@2.8.0-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.7.0-1",
        "2.7.1-2",
        "2.8.0-1"
      ]
    }
  ],
  "aliases": [],
  "details": "League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone \u003cscript or \u003ciframe line followed by a block supplying attributes like src or onload, executing stored scripts in viewers\u0027 browsers under default GFM settings.",
  "id": "UBUNTU-CVE-2026-105829",
  "modified": "2026-10-13T00:00:00Z",
  "published": "2026-10-13T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-105829"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-105829"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/thephpleague/commonmark/security/advisories/GHSA-97jj-33gv-5xf9"
    },
    {
      "type": "REPORT",
      "url": "https://www.vulncheck.com/advisories/league-commonmark-1.3.0-before-2.10.2-stored-xss-via-disallowedrawhtml-bypass"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-105829"
  ]
}

CVE-2026-105829 (GCVE-0-2026-105829)

Vulnerability from cvelistv5 – Published: 2026-10-08 14:10 – Updated: 2026-10-10 03:05

Title

League CommonMark 1.3.0 before 2.10.2 Stored XSS via DisallowedRawHtml Bypass

Summary

Severity

5.3 (Medium)


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

6.1 (Medium)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-10 03:05 UTC

CWE

CWE-80 - Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

Assigner

VulnCheck CNA under the mitre root

CNA scorecard B 84/100 over 6106 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/thephpleague/commonmark/securi…	vendor-advisory
https://www.vulncheck.com/advisories/league-commo…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
thephpleague	commonmark	cpe:2.3:a:thephpleague:commonmark:-:::::::*

Date Public

2026-09-21 00:00

Credits

4n86rakam1

Show details on NVD website

JSON

To clipboard

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        "metrics": [
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                "id": "CVE-2026-105829",
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                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-10T03:05:16.269227Z",
                "version": "2.0.3"
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          "packageURL": "pkg:composer/league/commonmark",
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      "metrics": [
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Sightings

Author	Source	Type	Date	Other

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.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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