Resource exhaustion in Thephpleague Commonmark
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.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/thephpleague/commonmark/security/advisories/GHSA-3q6v-r5mr-hxv8 (vendor-advisory)
- www.vulncheck.com/advisories/league-commonmark-2.0.0-before-2.10.2-quadratic-do… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-105830?
- CVE-2026-105830 is a high-severity vulnerability in Thephpleague Commonmark, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-10-08.
- How severe is CVE-2026-105830?
- High severity. CVSS v3 base score is 7.5 out of 10.