Bug 2521744 - CVE-2026-53583 libgit2: libgit2: Network attacker can intercept HTTPS connections via inverted IP SubjectAltName comparison [epel-all]
Summary: CVE-2026-53583 libgit2: libgit2: Network attacker can intercept HTTPS connect...
Keywords:
Status: ASSIGNED
Alias: None
Product: Fedora EPEL
Classification: Fedora
Component: libgit2
Version: epel10
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Fabio Valentini
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["8cf6c6b0-124c-4406-b0cc-b...
Depends On:
Blocks: CVE-2026-53583
TreeView+ depends on / blocked
 
Reported: 2026-08-24 07:55 UTC by Vladimir Vasilev
Modified: 2026-08-27 12:57 UTC (History)
5 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


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Description Vladimir Vasilev 2026-08-24 07:55:17 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.

Comment 1 Fabio Valentini 2026-08-27 12:57:58 UTC
I have been working on migrating applications from the out-of-support libgit2 v1.7 to libgit2_1.9:
https://lists.fedoraproject.org/archives/list/epel-devel@lists.fedoraproject.org/thread/BOJI6KPDIRTZZ7LZQW37RM7V7EK33DF7/#BOJI6KPDIRTZZ7LZQW37RM7V7EK33DF7


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