rsync: Improper Handling of Length Parameter Inconsistency
CVE-2026-41035 is a high-severity improper handling of length parameter inconsistency vulnerability in rsync from Samba, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected rsync versions: 3.0.1 through 3.4.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.41% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of rsync you run against the affected versions below, and install the vendor's latest release.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 2 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.4 | High | CNA (mitre.org) |
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.4 | High | CNA |
Official description
In rsync 3.0.1 through 3.4.1, receive_xattr relies on an untrusted length value during a qsort call, leading to a receiver use-after-free. The victim must run rsync with -X (aka --xattrs). On Linux, many (but not all) common configurations are vulnerable. Non-Linux platforms are more widely vulnerable.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Handling of Length Parameter Inconsistency
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
How developers prevent this class of flaw
- When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.
- Do not let the user control the size of the buffer.
- Validate that the length of the user-supplied data is consistent with the buffer size.
More Improper Handling of Length Parameter Inconsistency vulnerabilities (CWE-130)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/RsyncProject/rsync/releasesRelease Notes
Third-party and government advisories
- openwall.com/lists/oss-security/2026/04/16/9Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/04/22/3Mailing List, Third Party Advisory
Technical write-ups (may include proof of concept)
- openwall.com/lists/oss-security/2026/04/16/2Exploit, Mailing List, Third Party Advisory
Other references
- github.com/RsyncProject/rsync/issues/871Issue Tracking
- access.redhat.com/errata/RHSA-2026:17481
- access.redhat.com/errata/RHSA-2026:19152
- access.redhat.com/errata/RHSA-2026:19368
- access.redhat.com/errata/RHSA-2026:20601
- access.redhat.com/errata/RHSA-2026:20602
- access.redhat.com/errata/RHSA-2026:20603
- access.redhat.com/errata/RHSA-2026:20604
- access.redhat.com/errata/RHSA-2026:20696
- access.redhat.com/errata/RHSA-2026:23233
- access.redhat.com/errata/RHSA-2026:23245
- access.redhat.com/errata/RHSA-2026:25044
- access.redhat.com/errata/RHSA-2026:25149
- access.redhat.com/errata/RHSA-2026:25170
- access.redhat.com/errata/RHSA-2026:25172
Other vulnerabilities in rsync
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.4 High severity
Recent Improper Handling of Length Parameter Inconsistency vulnerabilities
- 7.5 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Spotted an error? Tell us.