Bug 2521757

Summary:	CVE-2026-53587 rust-libgit2-sys0.17: libgit2: Denial of Service due to heap out-of-bounds read from malicious Git server [epel-all]
Product:	[Fedora] Fedora EPEL	Reporter:	Vladimir Vasilev <vvasilev>
Component:	rust-libgit2-sys0.17	Assignee:	Rust SIG <rust-sig>
Status:	ASSIGNED ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	epel10	CC:	decathorpe, rust-sig
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["ebcd85d7-980a-4766-b836-173bb057110d"]}
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2520693

Description Vladimir Vasilev 2026-08-24 08:00:14 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, libgit2 performs a fixed-size strncmp in set_data in src/libgit2/transports/smart_pkt.c without first verifying that the smart-protocol pkt-line capability buffer contains 14 bytes. A malicious Git server can make bytes after the pkt-line complete object-format=, causing format_str to advance beyond the pkt-line and the following memchr length calculation to underflow. The resulting heap out-of-bounds walk can crash a client during the first refs-advertisement packet over HTTP, HTTPS, SSH, or the Git protocol. This issue is fixed in versions 1.8.6 and 1.9.5.

Comment 1 Fabio Valentini 2026-08-27 11:56:25 UTC

This is basically not fixable in rust-libgit2-sys0.17 since it is, specifically, a wrapper around libgit2 v1.7 only.

Almost all packages that use libgit2 via the Rust bindings have already been migrated to newer versions, and this package is already retired in F44+.

I'm looking into migrating the remaining users to rust-git2 v0.20+ on Fedora 43 and in EPEL too, at which point I would consider this issue resolved.

As far as I can tell, the only remaining package that uses rust-libgit2-sys0.17 in Fedora 43 and EPEL 9 is rust-git-absorb.