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Linux EUVDEUVD-2026-80439

| CVE-2026-89839
2026-09-16 Linux GHSA-hf9x-gfgm-hfj2

Lifecycle Timeline

2
Patch available
Sep 16, 2026 - 11:03 EUVD
CVE Published
Sep 16, 2026 - 10:31 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

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.

Analysis

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. …

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EUVD-2026-80439 vulnerability details – vuln.today

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