CVE-2026-53583
libgit2: libgit2: Network attacker can intercept HTTPS connections via inverted IP SubjectAltName comparison
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · August 21, 2026
Updated · August 25, 2026
Description
A flaw was found in libgit2, a C library for Git functionality. An inverted comparison in the OpenSSL backend's certificate verification logic, specifically when handling IP-literal hosts and certificate IP SubjectAltNames, allows a network attacker to intercept HTTPS connections. By presenting a CA-trusted certificate with any IP SubjectAltName, an attacker can trick libgit2 into accepting a mismatched IP address, leading to the interception of sensitive communication.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
CVSS / CWE
CVSS 3.1 · 6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CWE-295 · Improper Certificate Validation