Description
cmark-gfm is an extended version of the C reference implementation of CommonMark, a rationalized version of Markdown syntax with a spec. Three polynomial time complexity issues in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. These vulnerabilities have been patched in 0.29.0.gfm.12.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| github | cmark-gfm | < 0.29.0.gfm.12 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | cmark-gfm | 0.29.0.gfm.13-1 | — |
| Debian 14 | python-cmarkgfm | 2024.11.20-1 | — |
| Debian 14 | r-cran-commonmark | 1.9.1-1 | — |
| Debian 14 | ruby-commonmarker | 0.23.10-1 | — |
| Debian 13 | cmark-gfm | 0.29.0.gfm.13-1 | — |
| Debian 13 | python-cmarkgfm | 2024.11.20-1 | — |
| Debian 13 | r-cran-commonmark | 1.9.1-1 | — |
| Debian 13 | ruby-commonmarker | 0.23.10-1 | — |
| Debian 12 | cmark-gfm +3 | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-cmarkgfm | 2025.10.22-1.4 | openSUSE-SU-2026:12003-1 |
Advisories 1
- openSUSE-SU-2026:12003-1 python313-cmarkgfm-2025.10.22-1.4 on GA media SUSE / openSUSE Security Updates · Oct 5, 2026