Bug 2521808

Summary: CVE-2026-70463 rsync: rsync: Authorization bypass via `auth users` directive parsing [fedora-all]
Product: [Fedora] Fedora Reporter: Srikanth Balasubramanian <sbalasub>
Component: rsyncAssignee: Michal Ruprich <mruprich>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: luhliari, mruprich, ssorce
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["2cd44718-6762-4fd5-aa49-d3830265e130"]}
Fixed In Version: rsync-3.5.0-1.fc43 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-08-27 01:12:26 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2515385    

Description Srikanth Balasubramanian 2026-08-24 11:16:17 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.

Comment 1 Fedora Update System 2026-08-26 06:55:09 UTC
FEDORA-2026-d6763b4c84 (rsync-3.5.0-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-d6763b4c84

Comment 2 Fedora Update System 2026-08-27 01:12:26 UTC
FEDORA-2026-d6763b4c84 (rsync-3.5.0-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.