hsec-2025-0007
Vulnerability from osv_haskell
cmark-gfm: resource exhaustion due to quadratic complexity in parser
cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and
rendering library and program in C. A polynomial time complexity
issue in cmark-gfm may lead to unbounded resource exhaustion and
subsequent denial of service, due to quadratic complexity issues
when parsing text which leads with either large numbers of > or
- characters.
The Haskell cmark-gfm package bundles the C sources and was
affected by this issue. This fix was released in the upstream C
package at version 0.29.0.gfm.10. Version 0.2.6 of the Haskell
package adopted the fix (moving from 0.29.0.gfm.6 to
0.29.0.gfm.13). Packages that depend on cmark-gfm should update
to 0.2.6 or later.
Users unable to update should avoid processing data from untrusted sources or validate the input with other tools before using cmark-gfm to parse it.
Pandoc < 2.10.1 depended on cmark-gfm and could be affected by
this issue.
{
"affected": [
{
"database_specific": {
"human_link": "https://github.com/haskell/security-advisories/tree/main/advisories/published/2025/HSEC-2025-0007.md",
"osv": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export/2025/HSEC-2025-0007.json"
},
"package": {
"ecosystem": "Hackage",
"name": "cmark-gfm"
},
"ranges": [
{
"events": [
{
"introduced": "0.1.0"
},
{
"fixed": "0.2.6"
}
],
"type": "ECOSYSTEM"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
],
"aliases": [
"CVE-2023-24824",
"GHSA-66g8-4hjf-77xh"
],
"database_specific": {
"home": "https://github.com/haskell/security-advisories",
"osvs": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export",
"repository": "https://github.com/haskell/security-advisories"
},
"details": "# cmark-gfm: resource exhaustion due to quadratic complexity in parser\n\n*cmark-gfm* is GitHub\u0027s fork of *cmark*, a CommonMark parsing and\nrendering library and program in C. A polynomial time complexity\nissue in cmark-gfm may lead to unbounded resource exhaustion and\nsubsequent denial of service, due to quadratic complexity issues\nwhen parsing text which leads with either large numbers of `\u003e` or\n`-` characters.\n\nThe Haskell *cmark-gfm* package bundles the C sources and was\naffected by this issue. This fix was released in the upstream C\npackage at version `0.29.0.gfm.10`. Version `0.2.6` of the Haskell\npackage adopted the fix (moving from `0.29.0.gfm.6` to\n`0.29.0.gfm.13`). Packages that depend on *cmark-gfm* should update\nto `0.2.6` or later.\n\nUsers unable to update should avoid processing data from untrusted\nsources or validate the input with other tools before using\n*cmark-gfm* to parse it.\n\nPandoc `\u003c 2.10.1` depended on *cmark-gfm* and could be affected by\nthis issue.\n",
"id": "HSEC-2025-0007",
"modified": "2025-12-27T08:58:56Z",
"published": "2025-12-27T08:58:56Z",
"references": [
{
"type": "FIX",
"url": "https://github.com/kivikakk/cmark-gfm-hs/commit/1359b8740c6b29dde0ad8f816531112b32eb8cbe"
},
{
"type": "FIX",
"url": "https://github.com/github/cmark-gfm/commit/2300c1bd2c8226108885bf019655c4159cf26b59"
},
{
"type": "ADVISORY",
"url": "https://github.com/github/cmark-gfm/security/advisories/GHSA-66g8-4hjf-77xh"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-24824"
}
],
"schema_version": "1.5.0",
"summary": "cmark-gfm: resource exhaustion due to quadratic complexity in parser"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.