CVE-2026-53583

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, verify_server_cert in src/libgit2/streams/openssl.c uses an inverted !!memcmp result in the GEN_IPADD branch when comparing an IP-literal host with a certificate IP SubjectAltName. OpenSSL builds reject matching IP addresses and accept mismatched IP addresses, allowing a network attacker with a CA-trusted certificate containing any IP SubjectAltName to intercept libgit2 connections to IP-literal HTTPS URLs. DNS SubjectAltName validation and non-OpenSSL TLS backends are not affected. This issue is fixed in versions 1.8.6 and 1.9.5.

• CWE-295
• CWE-297

• https://github.com/libgit2/libgit2/commit/647dcb432980b84ede4cb5a008bbd1ccb4ead03d
• https://github.com/libgit2/libgit2/commit/c2aa35409ee0e6515df64da49750f13a0a42c47f
• https://github.com/libgit2/libgit2/commit/ef086bc3e4eedf62be38a910381aae24d49871ff
• https://github.com/libgit2/libgit2/releases/tag/v1.8.6
• https://github.com/libgit2/libgit2/releases/tag/v1.9.5
• https://github.com/libgit2/libgit2/security/advisories/GHSA-h7gc-w2gg-p9xp
• https://github.com/libgit2/libgit2/security/advisories/GHSA-h7gc-w2gg-p9xp

Published

Aug 20, 2026

Last Modified

Sep 9, 2026

Status

Awaiting Analysis

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-53577Kestra is an open-source, event-driven orchestration platfor…6.5
• CVE-2026-53578Trilium is an open-source hierarchical note-taking applicati…9.3
• CVE-2026-53579Trilium is an open-source hierarchical note-taking applicati…9.3
• CVE-2026-5358Rejected reason: REJECTED: CVE-2026-5358 is rejected for two…
• CVE-2026-53580Trilium is an open-source hierarchical note-taking applicati…8.1
• CVE-2026-53581OPNsense is a FreeBSD based firewall and routing platform. P…9
• CVE-2026-53584libgit2 is a portable C implementation of the Git core metho…4.3
• CVE-2026-53585libgit2 is a portable C implementation of the Git core metho…5.3
• CVE-2026-53586libgit2 is a portable C implementation of the Git core metho…6.5
• CVE-2026-53587libgit2 is a portable C implementation of the Git core metho…7.5
• CVE-2026-5359Rejected reason: ** REJECT ** DO NOT USE THIS CANDIDATE NUMB…
• CVE-2026-53591FreeScout is a free help desk and shared inbox built with PH…8.6