DEBIAN-CVE-2026-86429

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Source
https://security-tracker.debian.org/tracker/CVE-2026-86429
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86429.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-86429
Upstream
Published
2026-09-07T13:20:42Z
Modified
2026-09-20T09:00:07Z
Severity
  • 8.7 (High) CVSS_V4 - 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 CVSS Calculator
Summary
[none]
Details

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.

References

Affected packages

Debian:12 / php-league-commonmark

Package

Name
php-league-commonmark
Purl
pkg:deb/debian/php-league-commonmark?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.3.9-1
2.3.9-1+deb12u1
2.4.0-1
2.4.1-1
2.4.2-1
2.4.2-2
2.5.0-1
2.5.1-1
2.5.3-1
2.6.0-1
2.6.1-1
2.6.1-2
2.6.2-1
2.7.0-1
2.7.1-1
2.7.1-2
2.8.0-1
2.8.1-1
2.8.2-1
2.8.2-2
2.8.3-1
2.9.0-1
2.10.0-1
2.10.1-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86429.json"

Debian:13 / php-league-commonmark

Package

Name
php-league-commonmark
Purl
pkg:deb/debian/php-league-commonmark?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.7.0-1
2.7.0-1+deb13u1
2.7.1-1
2.7.1-2
2.8.0-1
2.8.1-1
2.8.2-1
2.8.2-2
2.8.3-1
2.9.0-1
2.10.0-1
2.10.1-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86429.json"

Debian:14 / php-league-commonmark

Package

Name
php-league-commonmark
Purl
pkg:deb/debian/php-league-commonmark?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.10.0-1

Affected versions

2.*
2.7.0-1
2.7.1-1
2.7.1-2
2.8.0-1
2.8.1-1
2.8.2-1
2.8.2-2
2.8.3-1
2.9.0-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86429.json"