Bug 2531024

Summary: CVE-2026-29518 rsync: TOCTOU symlink race condition allowing local privilege escalation in daemon mode without chroot. [fedora-all]
Product: [Fedora] Fedora Reporter: Patrick Del Bello <pdelbell>
Component: rsyncAssignee: Michal Ruprich <mruprich>
Status: CLOSED CURRENTRELEASE 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": ["18aada90-6d23-4616-ac21-5e3f4aa6a555"]}
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-09-11 12:11:22 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: 2469055    

Description Patrick Del Bello 2026-09-09 15:28:59 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.

A flaw was found in rsync. An rsync daemon configured with "use chroot = no" is exposed
to a time-of-check / time-of-use race on parent path components. A local
attacker with write access to a module can replace a parent directory
component with a symlink between the receiver's check and its open(),
redirecting reads (basis-file disclosure) and writes (file overwrite)
outside the module. Under elevated daemon privilege this allows privilege
escalation. Default "use chroot = yes" is not exposed.
Comment 1 Michal Ruprich 2026-09-11 12:11:22 UTC 
Fixed in the currently released version of rsync. Closing.