CVE catalog
CVE-2026-86429
The league/commonmark (thephpleague/commonmark) library in versions >= 1.5.0 and < 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension
- Severity
- High · CVSS 8.7
CVSS: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
- 0.52% · Oct 25, 2026
The league/commonmark (thephpleague/commonmark) library in versions >= 1.5.0 and < 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents — such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes — to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | php-league-commonmark | sid | 2.10.4-1 | fixed |
| Debian | php-league-commonmark | forky | 2.10.4-1 | fixed |
| Debian | php-league-commonmark | trixie | 2.7.0-1+deb13u1 | vulnerable |
| Debian | php-league-commonmark | bookworm | 2.3.9-1+deb12u1 | vulnerable |
| Cpe | commonmark | Not reported | 2.9.1 | fixed |
| Ubuntu | php-league-commonmark | pro | 2.3.9-1 | vulnerable |
| Ubuntu | php-league-commonmark | pro | 2.4.1-1 | vulnerable |
| Ubuntu | php-league-commonmark | pro | 2.4.2-1 | vulnerable |
| Ubuntu | php-league-commonmark | pro | 2.4.2-2 | vulnerable |
| Ubuntu | php-league-commonmark | pro | 2.4.2-2ubuntu0.1~esm1 | vulnerable |
| Ubuntu | php-league-commonmark | 26.04 | 2.7.0-1 | vulnerable |
| Ubuntu | php-league-commonmark | 26.04 | 2.7.1-2 | vulnerable |
| Ubuntu | php-league-commonmark | 26.04 | 2.8.0-1 | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | php-league-commonmark | source | sid | 2.10.0-1 | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | forky | 2.10.0-1 | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Cpe | commonmark | cpe | Not reported | 2.9.1 | Not reported | NVD-CVE-2026-86429 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [php-league-commonmark]Affected
Details (2)
2.3.9-1+deb12u1· all · bookwormAffected
nvd · php-league-commonmark · debian · bookworm; nvd · php-league-commonmark · debian · 12
2.3.9-1+deb12u1· all · bookwormAffected
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 · trixieAffected
nvd · php-league-commonmark · debian · 13
2.7.0-1+deb13u1· all · trixieAffected
nvd · php-league-commonmark · debian · 13
Observed:
References
- [https://nvd.nist.gov/vuln/detail/CVE-2026-86429]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-86429]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-86429]
- [https://security-tracker.debian.org/tracker/CVE-2026-86429]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]