CVE-2026-119741
Description
A flaw was found in rsync. An unauthenticated remote attacker can cause a Denial of Service (DoS) by sending crafted checksum sequences during delta file transfers to a public rsync server. This flaw forces the server to perform excessive checksum computations across consecutive data offsets, leading to high CPU resource exhaustion that degrades or disrupts availability for legitimate users.
Statement
Red Hat has rated this vulnerability as Important because an unauthenticated remote attacker accessing a public rsync daemon module can trigger excessive CPU consumption during delta transfers. Repeated or concurrent malicious transfers can exhaust processing capacity and disrupt service for legitimate users. Exposure depends on serving files to untrusted receivers; systems that do not provide such access are not exposed to this unauthenticated attack scenario.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
--- CME Mitigation Guidance (2026-11-06) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.
The highest-value action is to bound delta-transfer strong-checksum calculations and eliminate redundant collision lookups in rsync hash_search(): upgrade to the corresponding fixed Red Hat builds, which unlink duplicate false-alarm hash chain entries sharing identical strong checksums and advance offset by a full block after four consecutive unmatched weak checksum collisions, closing all 2 injection vectors (crafted weak-checksum collision sequences with mismatched strong checksums, duplicate colliding block hash chains). Until patched, this is a concern on rsync daemon deployments serving delta transfers to unauthenticated or untrusted receivers, so restrict network access to rsync daemon modules or disable unauthenticated delta file transfers from untrusted receivers. As a compensating measure, Apply RLIMIT_CPU limits to rsync worker processes using ulimit or prlimit to contain excessive CPU consumption during delta checksum searches and Throttle incoming connection rates and concurrent sessions per IP to mitigate repeated unauthenticated delta transfer DoS attempts. These controls limit blast radius and contain exploitation, but they do not fix the underlying algorithmic complexity defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-114 Process Resource Limits (ulimit/prlimit) (medium)
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
The typical consequence is CPU consumption, but memory consumption and consumption of other resources can also occur.
Frequently Asked Questions
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