CVE catalog

CVE-2026-86433

commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling lis

[CVE catalog]

Severity
High · CVSS 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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
Published
Updated
Source
[NVD] · [CVE record]
EPSS
0.51% · Oct 25, 2026

commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

DistributionPackageReleaseVersionStatus
Debianphp-league-commonmarksid2.10.4-1fixed
Debianphp-league-commonmarkforky2.10.4-1fixed
Debianphp-league-commonmarktrixie2.7.0-1+deb13u1vulnerable
Debianphp-league-commonmarkbookworm2.3.9-1+deb12u1vulnerable
Ubuntuphp-league-commonmarkpro2.3.9-1vulnerable
Ubuntuphp-league-commonmarkpro2.4.1-1vulnerable
Ubuntuphp-league-commonmarkpro2.4.2-1vulnerable
Ubuntuphp-league-commonmarkpro2.4.2-2vulnerable
Ubuntuphp-league-commonmarkpro2.4.2-2ubuntu0.1~esm1vulnerable
Ubuntuphp-league-commonmark26.042.7.0-1vulnerable
Ubuntuphp-league-commonmark26.042.7.1-2vulnerable
Ubuntuphp-league-commonmark26.042.8.0-1vulnerable

Fixed-version evidence

DistributionPackageTypeReleaseFixed versionUrgencyOriginBugs
Debianphp-league-commonmarksourcesid2.9.0-1not yet assignedNot reportedNot reported
Debianphp-league-commonmarksourceforky2.9.0-1not yet assignedNot reportedNot reported
Debianphp-league-commonmarksourcetrixie(unfixed)not yet assignedNot reportedNot reported
Debianphp-league-commonmarksourcebookworm(unfixed)not yet assignedNot reportedNot reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

  • [php-league-commonmark]Affected
    Details (2)

    • 2.3.9-1+deb12u1 · all · bookworm

      Affected

      nvd · php-league-commonmark · debian · bookworm; nvd · php-league-commonmark · debian · 12

    • 2.3.9-1+deb12u1 · all · bookworm

      Affected

      nvd · php-league-commonmark · debian · bookworm; nvd · php-league-commonmark · debian · 12

[Debian 13 (Trixie)]

  • [php-league-commonmark]Affected
    Details (2)

    • 2.7.0-1+deb13u1 · all · trixie

      Affected

      nvd · php-league-commonmark · debian · 13

    • 2.7.0-1+deb13u1 · all · trixie

      Affected

      nvd · php-league-commonmark · debian · 13

Observed:

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]