CVE-2026-70455

high

Description

rsync 3.4.2 before 3.5.0 contains a denial of service vulnerability that allows a remote sender to exhaust system resources by specifying the --zt short alias for --compress-threads, which bypasses the refuse options directive's string matching on long option names. Attackers can specify --zt=N with a large value to spawn an unbounded number of Zstandard worker threads on the receiver, exhausting available thread and memory resources.

References

https://www.vulncheck.com/advisories/rsync-dos-via-zt-zstandard-compression-thread-exhaustion

https://github.com/RsyncProject/rsync/security/advisories/GHSA-rjvj-qgqg-cvx9

https://github.com/RsyncProject/rsync/releases/tag/v3.5.0

Details

Source: Mitre, NVD

Published: 2026-08-13

Updated: 2026-08-13

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: High

CVSS v4

Base Score: 8.7

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Severity: High