CVE-2026-52791: fuse-overlayfs release-1.x preserves SUID/SGID bits after truncate/open(O_TRUNC)

Severity: low (CVSS 2.0 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-29 · updated 2026-10-24
Weakness: CWE-266

Description

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.

Affected products

containers fuse-overlayfs: before 1.17

References

https://github.com/containers/fuse-overlayfs/commit/97e0d968a782fc259ebde112db1e9b9ff1ad724f
https://github.com/containers/fuse-overlayfs/releases/tag/v1.17
https://github.com/containers/fuse-overlayfs/security/advisories/GHSA-2cc4-p72c-v85h
https://github.com/containers/fuse-overlayfs/security/advisories/GHSA-2cc4-p72c-v85h

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