CVE-2026-53587

A flaw was found in libgit2. A fixed-size string comparison in the set_data function within transports/smart_pkt.c does not adequately verify the size of a network packet buffer. A remote attacker, operating a malicious Git server, can send a specially crafted packet-line capability buffer. This can lead to a heap out-of-bounds read, causing the client application to crash and resulting in a Denial of Service (DoS).

This flaw is rated with an Important impact for Red Hat products because an unauthenticated remote server can trigger an out-of-bounds memory read that terminates client applications utilizing libgit2 without requiring user interaction beyond initiating a network connection. In typical deployments, the vulnerability is exposed whenever developer utilities, build pipelines, or containerized services perform fetch or clone operations against an untrusted upstream Git repository. Because the issue is confined to abnormal client termination during initial handshake negotiations, it results in a denial of service without compromising host integrity or disclosing sensitive system data.

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 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.