CVE-2026-53788: rsync < 3.5.0 Newline Injection via name-converter uid/gid mapping

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-13 · updated 2026-10-24
Weakness: CWE-93

Description

rsync before 3.5.0 contains a newline injection vulnerability in the name-converter uid/gid mapping interface that allows local attackers to forge protocol messages by creating user or group names containing newline characters. Attackers can inject malicious newline characters into names communicated over the pipe-based line-oriented protocol to cause the rsync daemon to process attacker-influenced data as legitimate protocol input, corrupting uid/gid mapping logic.

Affected products

RsyncProject rsync: through 3.4.4

References

https://github.com/RsyncProject/rsync/releases/tag/v3.5.0
https://github.com/RsyncProject/rsync/security/advisories/GHSA-p4c5-8c68-5fjq
https://www.vulncheck.com/advisories/rsync-newline-injection-via-name-converter-uid-gid-mapping

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