CVE-2026-86428CWE-407

CVE-2026-86428

High · published September 7, 2026

CVSS v3.1
7.5
EPSS
0%
Percentile
41.4
In the wild
Unconfirmed
What it is

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming disproportionate CPU resources and preventing legitimate requests from completing.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
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
EPSS
0.00493 · 41.4th percentile
Weakness
CWE-407 · Inefficient Algorithmic Complexity
Published
2026-09-07T17:20Z
Affected products (1)
ProductVersionsFixed in
thephpleague/commonmark≥ 1.5.0, < 2.10.02.10.0
References (2)
https://github.com/thephpleague/commonmark/security/advisories/GHSA-8rr7-cvq3-gmfh · [email protected]https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.10.0-denial-of-service-via-attributes · [email protected]
EPSS history
Timeline
  • 09 SEP 03:20Z
    EPSS moved — → 0%
    epss
  • 07 SEP 12:53Z
    commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes
    cvelistv5