{"id":"CVE-2026-53583","title":"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","summary":"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/stream…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","cwe":["CWE-295","CWE-297"],"published":"2026-08-20","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:19:49.197","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53583","references":[{"url":"https://github.com/libgit2/libgit2/commit/647dcb432980b84ede4cb5a008bbd1ccb4ead03d","label":"security-advisories@github.com"},{"url":"https://github.com/libgit2/libgit2/commit/c2aa35409ee0e6515df64da49750f13a0a42c47f","label":"security-advisories@github.com"},{"url":"https://github.com/libgit2/libgit2/commit/ef086bc3e4eedf62be38a910381aae24d49871ff","label":"security-advisories@github.com"},{"url":"https://github.com/libgit2/libgit2/releases/tag/v1.8.6","label":"security-advisories@github.com"},{"url":"https://github.com/libgit2/libgit2/releases/tag/v1.9.5","label":"security-advisories@github.com"},{"url":"https://github.com/libgit2/libgit2/security/advisories/GHSA-h7gc-w2gg-p9xp","label":"security-advisories@github.com"},{"url":"https://github.com/libgit2/libgit2/security/advisories/GHSA-h7gc-w2gg-p9xp","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd"],"epss":0.00192,"epssPercentile":0.0909,"ingestedAt":"2026-09-09T21:22:45.545Z","slug":"CVE-2026-53583","body":"## Overview\n\nlibgit2 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}