rsync sender denial of service via hash_search() checksum collisions
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 8 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-407.
Summary
rsync through 3.5.1 contains a denial of service flaw in the delta-transfer sender's hash_search() function. The flaw is an inefficient algorithm (CWE-407) that lets the sender do unbounded strong-checksum work at consecutive offsets. An unauthenticated attacker pulling from a public daemon module can exhaust sender CPU across concurrent connections using colliding weak checksums.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade rsync to version 3.5.2, which fixes this flaw. Red Hat Enterprise Linux 6, 7, 8, 9 and 10, Red Hat Hardened Images, and Red Hat OpenShift Container Platform 4 and 5 are affected, and Red Hat lists no available plan for them.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
- Fix · CNA rsync (RsyncProject) Fixed in 3.5.2
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix yet |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat Hardened Images | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Timeline
- 2026-11-03 Threatist record created from CVE-2026-119741
- 2026-11-03 CISA SSVC decision points changed
- 2026-11-03 Alias added: GHSA-56w4-j8c7-xvrw
- 2026-11-04 Title updated · CNA
- 2026-11-04 Fix available: RsyncProject/[email protected] · CNA
- 2026-11-04 1 new reference · CNA
- 2026-11-05 Affected versions changed · Red Hat
- 2026-11-05 CVSS score added · Red Hat
References
More Samba Rsync vulnerabilities
- TI-2024-11208 Rsync: heap buffer overflow in rsync due to improper checksum length handling CVSS 3.1CRITICAL 9.8
- TI-2024-11209 Rsync: info leak via uninitialized stack contents CVSS 3.1HIGH 7.5
- TI-2024-11212 Rsync: --safe-links option bypass leads to path traversal CVSS 3.1HIGH 7.5
- TI-2024-11211 Rsync: path traversal vulnerability in rsync CVSS 3.1HIGH 7.5
- TI-2024-11210 Rsync: rsync server leaks arbitrary client files CVSS 3.1MEDIUM 6.8
- TI-2017-12160 The receive_xattr function in xattrs.c in rsync 3.1.2 and 3.1.3-development does not… CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-119741 · CVE Program
- CVE-2026-119741 · NVD
- FIRST EPSS
- GHSA-56w4-j8c7-xvrw · GitHub Advisory Database · CC BY 4.0
- CVE-2026-119741 · Red Hat security data · CC BY 4.0
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