Resource exhaustion in Libgit2
CVE-2026-53585
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.005 (43.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 43.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- Libgit2 — versions < 1.8.6, >= 1.9.0, < 1.9.5
Weakness classification (CWE)
References
- github.com/libgit2/libgit2/security/advisories/GHSA-27m5-gxxh-x79j
- github.com/libgit2/libgit2/commit/0cdfdd5fa8f8514c82413025e1e0808866cf7c30
- github.com/libgit2/libgit2/commit/c1896f06df22cc0ca5658df3a8f6cd7ede4cd6ae
- github.com/libgit2/libgit2/commit/dec22ac01ad9620c96b7b9ac3ef636ea46d43bed
- github.com/libgit2/libgit2/releases/tag/v1.8.6
- github.com/libgit2/libgit2/releases/tag/v1.9.5
Frequently asked questions
- What is CVE-2026-53585?
- CVE-2026-53585 is a medium-severity vulnerability in Libgit2, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.3/10. Published 2026-08-20.
- How severe is CVE-2026-53585?
- Medium severity. CVSS v3 base score is 5.3 out of 10.