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CVE-2026-89839

Unknown

Last modified

CVE-2026-89839 is a vulnerability of currently unknown severity. 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..

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 01beba7957a26f9b7179127e8ad56bb5a0f56138, < 4c0c610b480cfbc57528aa1acbd6be12ed2a6fb1; >= 01beba7957a26f9b7179127e8ad56bb5a0f56138, < c3e2692c7a58e0bdb84bd658d827e89dcecea3ad; >= 01beba7957a26f9b7179127e8ad56bb5a0f56138, < 3b681229e9f8fb1dd29bc65983bf3c87779e4ca3; >= 01beba7957a26f9b7179127e8ad56bb5a0f56138, < ab31e3b774f5d06b4489cef6c297b48c47c9dcbd; >= 01beba7957a26f9b7179127e8ad56bb5a0f56138, < a54ffce4637acb0db8e695188a6c7f99f14c3576
LinuxLinux6.3

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89839?
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.
How severe is CVE-2026-89839?
Severity scoring for CVE-2026-89839 is pending analysis.
How do I fix CVE-2026-89839?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST