CVE-2026-44508
Rsync is a file-copying tool that uses a delta-transfer algorithm to synchronize remote and local files. In versions prior to 3.4.3, the receiver's compressed-token decoder accumulated a 32-bit signed counter without checking for overflow. A malicious sender can trigger an overflow that with careful manipulation can lead to the extraction of data stored in memory of the process allowing an attacker to access environment variables, passwords and memory pointers from the heap, stack, and libraries. The leakage of these pointers and data can significantly reduce the effectiveness of ASLR and facilitate further exploitation. This issue is fixed in version 3.4.3.
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Severity metrics
CVSS 3.1 : 8.1 HIGH
Vector: AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.