{"id":"CVE-2026-70455","summary":"rsync 3.4.2 \u003c 3.5.0 DoS via --zt Zstandard Compression Thread Exhaustion","details":"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.","aliases":["GHSA-rjvj-qgqg-cvx9"],"modified":"2026-08-17T03:55:03.829743110Z","published":"2026-08-13T14:45:11.164Z","database_specific":{"cna_assigner":"VulnCheck","cwe_ids":["CWE-770"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/70xxx/CVE-2026-70455.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/70xxx/CVE-2026-70455.json"},{"type":"ADVISORY","url":"https://github.com/RsyncProject/rsync/releases/tag/v3.5.0"},{"type":"ADVISORY","url":"https://github.com/RsyncProject/rsync/security/advisories/GHSA-rjvj-qgqg-cvx9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-70455"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/rsync-dos-via-zt-zstandard-compression-thread-exhaustion"},{"type":"PACKAGE","url":"https://github.com/RsyncProject/rsync"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/rsyncproject/rsync","events":[{"introduced":"de3cc03b03be153092f266aa1117b4706947ed07"},{"fixed":"471e17dc0d68233db84db11be82c9f62f4661214"}],"database_specific":{"extracted_events":[{"introduced":"3.4.2"},{"last_affected":"3.4.4"},{"fixed":"3.5.0"}],"source":["AFFECTED_FIELD","DESCRIPTION","REFERENCES"]}}],"versions":["v3.4.3","v3.4","v3.4.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-70455.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}