CVE-2026-86428
highcommonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes.
Vendor / product: Thephpleague — commonmark
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.
CVSS
7.5
7.5 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Severity source: NVD CVSS v3.1 (disclosure@vulncheck.com)
Timeline (UTC)
Published: 2026-09-07 13:20
Modified: 2026-10-08 16:17
NVD status: Analyzed
Last synced 1 day ago
Verified against the source API 2026-10-27 06:51 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
thephpleague / commonmark ≥1.5.0 <2.10.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/thephpleague/commonmark/security/advisories/GHSA-8rr7-cvq3-gmfh disclosure@vulncheck.com
- https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.10.0-denial-of-service-via-... disclosure@vulncheck.com
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:51 UTC · record ↗