CVE-2026-53585: LIBGIT2

Medium severity, CVSS 5.3. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• LIBGIT2 LIBGIT2: before 1.8.6 (fixed in 1.8.6); from 1.9.0, before 1.9.5 (fixed in 1.9.5)

Published 2026-08-20. Last modified 2026-09-09.