containers fuse-overlayfs up to 1.16 File Mode main.c open/truncate privileges management

Summaryinfo

A vulnerability identified as very critical has been detected in containers fuse-overlayfs up to 1.16. This vulnerability affects the function open/truncate of the file main.c of the component File Mode Handler. This manipulation causes privileges management. This vulnerability is handled as CVE-2026-52791. It is possible to launch the attack on the local host. There is not any exploit available.

Detailsinfo

A vulnerability classified as very critical was found in containers fuse-overlayfs up to 1.16. Affected by this vulnerability is the function open/truncate of the file main.c of the component File Mode Handler. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-52791 since 06/08/2026. The exploitation appears to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/29/2026). The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 1.17 eliminates this vulnerability.

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Productinfo

Type

• Virtualization Software

Vendor

• containers

Name

• fuse-overlayfs

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16

Website

• Product: https://github.com/containers/fuse-overlayfs/

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