CVE-2026-70455rsync 3.4.2 < 3.5.0 DoS via --zt Zstandard Compression Thread Exhaustion
Updated under an hour ago ()
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It affects RsyncProject rsync and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-770
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Analyzed
- Record last updated
- Aug 14, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
RsyncProject rsync rsyncproject:rsync (from the name) | from 3.4.2 through 3.4.4; 3.5.0 not affected | CNA record |
samba rsync samba:rsync | from 3.4.2 before 3.5.0 | NVD |
References
- https://github.com/RsyncProject/rsync/security/advisories/GHSA-rjvj-qgqg-cvx9vendor-advisory
- https://github.com/RsyncProject/rsync/releases/tag/v3.5.0release-notes, product
- https://www.vulncheck.com/advisories/rsync-dos-via-zt-zstandard-compression-thread-exhaustionthird-party-advisory, release-notes
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.