UBUNTU-CVE-2026-53587

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.

References

Affected packages

Ubuntu:24.04:LTS / libgit2

Package

Name: libgit2
Purl: pkg:deb/ubuntu/libgit2?arch=source&distro=noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

1.7.2+ds-1ubuntu3.1

Affected versions

1.*

1.5.1+ds-1ubuntu1

1.7.1+ds-2ubuntu1

1.7.2+ds-1ubuntu1

1.7.2+ds-1ubuntu2

1.7.2+ds-1ubuntu3

Ecosystem specific

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "libgit2-1.7",
            "binary_version": "1.7.2+ds-1ubuntu3.1"
        },
        {
            "binary_name": "libgit2-fixtures",
            "binary_version": "1.7.2+ds-1ubuntu3.1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53587.json"

Ubuntu:26.04:LTS / libgit2