CVE-2026-119741: rsync < 3.5.2 Denial of Service via hash_search() Checksum Collisions
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-04 15:41 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
rsync before 3.5.2 contains a denial of service vulnerability in the delta-transfer sender’s hash_search() in match.c that allows malicious receivers to trigger unbounded strong-checksum work at consecutive offsets. Unauthenticated attackers pulling from a public daemon module can supply weak checksums colliding with consecutive rolling windows plus non-matching strong checksums, exhausting sender CPU across concurrent connections.
Description quoted from the CVE record (assigned by VulnCheck, published 2026-11-03).
Weakness: Inefficient Algorithmic Complexity
How it can be exploited
Exploitable over the network with low attack complexity with no special attack requirements needing no privileges and no user interaction. Impact: confidentiality none, integrity none, availability high. 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
CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: yes. Technical impact: partial.
Public exploit evidence (Exploit Observer)
Exploit Observer has no public exploit code naming this CVE. Check Exploit Observer for anything new.
Live scores
- EPSS
- 0.006
low predicted chance of attack - VEDAS
- 0.975
strong exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| RsyncProject rsync | up to and including 3.5.1 | 3.5.2 is not affected |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
Vendor guidance:
- Fixed Release Tag (release-notes)
- Pull Request #1132 (patch, issue-tracking)
- Patch Commit (patch)
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
Advisories on this CVE
- rsync 3.5.2 fixes CPU exhaustion flaw, Help Net Security reports (full advisory)
References
Vendor advisories and patches
- Fixed Release Tag (release-notes)
- Pull Request #1132 (patch, issue-tracking)
- Patch Commit (patch)
Technical analysis and advisories
- https://github.com/RsyncProject/rsync/blob/a7404a9a633cff28ee1602f328b9c3fa69cdbd04/testsuite/hashsearch-collision-skip_test.py (technical-description)
- VulnCheck Advisory: rsync through 3.5.1 Denial of Service via hash_search() Checksum Collisions (third-party-advisory)
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
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