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.

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 14% of CVEs (scores of 2026-10-25)

CWEs

CWE-295, CWE-297

Published

2026-08-20

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

References

• 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

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