CVE-2026-53585
libgit2: Unbounded Memory Allocation via Delta Object Result-Size Header
- State
- Published
- Severity
- 5.3 Medium
- Published
- Aug 20, 2026
- Updated
- Aug 25, 2026
- Reserved
- Jun 9, 2026
Description
libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | GitHub_M |
Weaknesses
- CWE-770 Allocation of Resources Without Limits or Throttling
Affected Products
| Product | Versions |
|---|---|
libgit2libgit2 |
|
References
- https://github.com/libgit2/libgit2/security/advisories/GHSA-27m5-gxxh-x79j
- https://github.com/libgit2/libgit2/commit/0cdfdd5fa8f8514c82413025e1e0808866cf7c30
- https://github.com/libgit2/libgit2/commit/c1896f06df22cc0ca5658df3a8f6cd7ede4cd6ae
- https://github.com/libgit2/libgit2/commit/dec22ac01ad9620c96b7b9ac3ef636ea46d43bed
- https://github.com/libgit2/libgit2/releases/tag/v1.8.6
- https://github.com/libgit2/libgit2/releases/tag/v1.9.5
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