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CVE-2026-86428

commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes

Published: Sep 7, 2026Updated: Sep 9, 2026 Sources: CVE List NVDCWE-407
7.5HIGH
NVD MITRE
EPSS Score
0.3%
Top 79.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Workaround Only
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-407

Affected Products

thephpleague
oss-projectaka league
commonmarkLibrary
OSS Libraries / generic-library

Exploitability

Workaround Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/thephpleague/commonmark/security/advisories/GHSA-8rr7-cvq3-gmfh
github.com
https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.10.0-denial-of-service-via-attributes
vulncheck.com

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