In the Linux kernel, the following vulnerability has been resolved:

f2fs: use the mount idmap for the owner check in f2fs_xattr_advise_set()

f2fs_xattr_advise_set() calls inode_owner_or_capable() with &nop_mnt_idmap
before allowing the "system.advise" xattr to be set, instead of the idmap
that the VFS passes to the ->set() handler.

f2fs supports idmapped mounts, so on such a mount this checks the caller's
fsuid against the unmapped on-disk owner rather than the mapped owner: the
actual owner can be wrongly denied with -EPERM and an unrelated caller
wrongly allowed. Pass the handler's idmap instead.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-4817-1 linux-6.12 security update
Debian DSA Debian DSA DSA-6528-1 linux security update
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 18 Sep 2026 09:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-285

Wed, 16 Sep 2026 10:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: f2fs: use the mount idmap for the owner check in f2fs_xattr_advise_set() f2fs_xattr_advise_set() calls inode_owner_or_capable() with &nop_mnt_idmap before allowing the "system.advise" xattr to be set, instead of the idmap that the VFS passes to the ->set() handler. f2fs supports idmapped mounts, so on such a mount this checks the caller's fsuid against the unmapped on-disk owner rather than the mapped owner: the actual owner can be wrongly denied with -EPERM and an unrelated caller wrongly allowed. Pass the handler's idmap instead.
Title f2fs: use the mount idmap for the owner check in f2fs_xattr_advise_set()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-19T08:53:32.430Z

Reserved: 2026-09-11T19:38:34.769Z

Link: CVE-2026-89839

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-16T11:16:50.727

Modified: 2026-10-19T09:18:27.823

Link: CVE-2026-89839

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-18T09:00:08Z

Weaknesses