league/commonmark: Denial of service via crafted code fences, reference links, and emphasis delimiters

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.0049, the 42nd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

1. 31 Oct 2026, 14:06 UTC First seen by agentprime
2. 31 Oct 2026, 14:06 UTC Confirmed by OSV

Sources

• GitHub Advisory Database: GHSA-j8pm-gj4c-rq4x
• OSV: GHSA-j8pm-gj4c-rq4x
• github.com/thephpleague/commonmark/security/advisories/GHSA-j8pm-gj4c-rq4x
• github.com/thephpleague/commonmark/commit/0768217751fbfaeb8d76762f6944e9af7114295e
• github.com/thephpleague/commonmark/commit/d9375fadc308a63a02950a68d822417a6e4c33b2
• github.com/thephpleague/commonmark/commit/e0036ef031fd36ec1c3c82db8743fc928b5271c8
• github.com/thephpleague/commonmark
• github.com/thephpleague/commonmark/releases/tag/2.9.1

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.