# CVE-2026-119741: rsync through 3.5.1 Denial of Service via hash_search() Checksum Collisions

Status: published. Published: 2026-11-03. Updated: 2026-11-03.

rsync through 3.5.1 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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/RsyncProject/rsync/pull/1132
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/RsyncProject/rsync/commit/a7404a9a633cff28ee1602f328b9c3fa69cdbd04

## Affected products and versions

- RsyncProject / rsync (RsyncProject/rsync): ≥ 0; ≤ 3.5.1 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.7 (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; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: VulnCheck

- CVSS 4.0: 8.7 (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/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; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-407

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/RsyncProject/rsync/pull/1132 (CNA: VulnCheck; issue-tracking, patch)

- https://github.com/RsyncProject/rsync/commit/a7404a9a633cff28ee1602f328b9c3fa69cdbd04 (CNA: VulnCheck; patch)

- https://github.com/RsyncProject/rsync (CNA: VulnCheck; product)

- https://github.com/RsyncProject/rsync/blob/a7404a9a633cff28ee1602f328b9c3fa69cdbd04/testsuite/hashsearch-collision-skip_test.py (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/rsync-through-3.5.1-denial-of-service-via-hash-search-checksum-collisions (CNA: VulnCheck; third-party-advisory)

- https://github.com/RsyncProject/rsync (disclosure@vulncheck.com)

- https://github.com/RsyncProject/rsync/blob/a7404a9a633cff28ee1602f328b9c3fa69cdbd04/testsuite/hashsearch-collision-skip_test.py (disclosure@vulncheck.com)

- https://github.com/RsyncProject/rsync/commit/a7404a9a633cff28ee1602f328b9c3fa69cdbd04 (disclosure@vulncheck.com)

- https://github.com/RsyncProject/rsync/pull/1132 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/rsync-through-3.5.1-denial-of-service-via-hash-search-checksum-collisions (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-119741; retrieved 2026-11-03; source updated 2026-11-03

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-119741; retrieved 2026-11-03; source updated 2026-11-03

Revision: 9ec54c81de12816e530fddbbb51bb63de2ca8373b627e35d4dc46e1e680b422e

Canonical: https://y2.dev/cve/CVE-2026-119741

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