CVE-2026-70455
published 2026-08-13CVE-2026-70455: 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…
PriorityP341high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
0.57%
44.9th percentile
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.
Affected
3 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| rsyncproject | rsync | 3.4.2 – 3.4.4 | — |
| samba | rsync | — | — |
| samba | rsync | >= 3.4.2 < 3.5.0 | 3.5.0 |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv4.08.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat7.5HIGH
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Bugzilla
CVE-2026-70455 rsync: rsync: Denial of Service via Zstandard compression thread exhaustion [fedora-all]
bugzilla·2026-08-20·CVSS 7.5
CVE-2026-70455 [HIGH] CVE-2026-70455 rsync: rsync: Denial of Service via Zstandard compression thread exhaustion [fedora-all]
CVE-2026-70455 rsync: rsync: Denial of Service via Zstandard compression thread exhaustion [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
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.
Discussion:
FEDORA-2026-bfae8
Bugzilla
CVE-2026-70455 rsync: rsync: Denial of Service via Zstandard compression thread exhaustion
bugzilla·2026-08-13·CVSS 7.5
CVE-2026-70455 [HIGH] CVE-2026-70455 rsync: rsync: Denial of Service via Zstandard compression thread exhaustion
CVE-2026-70455 rsync: rsync: Denial of Service via Zstandard compression thread exhaustion
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.
2026-08-13
Published