Bug 2508489 (CVE-2026-52791)

Summary: CVE-2026-52791 fuse-overlayfs: fuse-overlayfs: Privilege Escalation Vulnerability via SUID/SGID Bit Preservation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in fuse-overlayfs, a component used for rootless containers. This vulnerability allows a low-privileged process to retain SUID (Set User ID) and SGID (Set Group ID) permissions on files after they are truncated or opened with the O_TRUNC flag. This can enable a local attacker to manipulate file permissions, potentially leading to privilege escalation within the system.
Story Points: ---
Clone Of: Environment:
Last Closed: 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: 2509242, 2509243, 2509244    
Bug Blocks:    

Description OSIDB Bzimport 2026-07-29 17:02:11 UTC
fuse-overlayfs is an implementation of overlayfs in FUSE for rootless containers. Prior to 1.17, the release-1.x C branch preserves SUID and SGID mode bits in main.c during open(O_TRUNC) and truncate handling on a copied-up file, allowing a low-privileged process to leave the upper-layer file with mode 4777. This issue is fixed in version 1.17.