Auth bypass in Rsyncproject Rsync
CVE-2026-70463
rsync 3.1.0 before 3.5.0 contains an authorization bypass in auth users directive parsing. The auth users parser uses comma-only tokenization when splitting the user list, which fails to correctly handle entries of the form @Group Name where the group name contains a space. The space within the group name causes the parser to split the entry at the space boundary, discarding the deny rule associated with the group. An authenticated user whose username or group membership would be denied by an @Group Name auth users entry can connect to a restricted module because the deny rule is silently discarded during parsing.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (38.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 38.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.001
Affected products
- Rsyncproject Rsync — versions 3.1.0, 3.5.0
- Samba Rsync
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/RsyncProject/rsync/releases/tag/v3.5.0 (release-notes, Product, Release Notes)
- github.com/RsyncProject/rsync/security/advisories/GHSA-pfj8-79vq-xgvr (vendor-advisory, Vendor Advisory)
- www.vulncheck.com/advisories/rsync-authorization-bypass-via-auth-users-directiv… (Third Party Advisory, Release Notes, third-party-advisory)
Frequently asked questions
- What is CVE-2026-70463?
- CVE-2026-70463 is a high-severity vulnerability in Rsyncproject Rsync, classified under Incorrect Authorization. CVSS score: 8.1/10. Published 2026-08-13.
- How severe is CVE-2026-70463?
- High severity. CVSS v3 base score is 8.1 out of 10.
- Is CVE-2026-70463 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.