CVE-2026-105830

league/commonmark from 2.0.0 before 2.10.2 contains a quadratic-time denial of service vulnerability in the GitHub Flavored Markdown Table extension's TableStartParser::tryStart() block-start scan. Unauthenticated attackers can submit a large paragraph of pipe-free lines not starting with letters, forcing repeated full-buffer strpos scans that exhaust PHP worker CPU.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-25)

CWE

CWE-400

Published

2026-10-08

Modified

2026-10-08

Record from

the NVD, synced 2026-10-19

References

• https://github.com/thephpleague/commonmark/security/advisories/GHSA-3q6v-r5mr-hxv8
• https://www.vulncheck.com/advisories/league-commonmark-2.0.0-before-2.10.2-quadratic-dos-via-tablestartparser
• https://github.com/thephpleague/commonmark/security/advisories/GHSA-3q6v-r5mr-hxv8

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