CVE-2026-89839

Summary

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

VendorProductVersion RangeStatus
LinuxLinux01beba7957a26f9b7179127e8ad56bb5a0f56138 < 4c0c610b480cfbc57528aa1acbd6be12ed2a6fb1affected
LinuxLinux01beba7957a26f9b7179127e8ad56bb5a0f56138 < c3e2692c7a58e0bdb84bd658d827e89dcecea3adaffected
LinuxLinux01beba7957a26f9b7179127e8ad56bb5a0f56138 < 3b681229e9f8fb1dd29bc65983bf3c87779e4ca3affected
LinuxLinux01beba7957a26f9b7179127e8ad56bb5a0f56138 < ab31e3b774f5d06b4489cef6c297b48c47c9dcbdaffected
LinuxLinux01beba7957a26f9b7179127e8ad56bb5a0f56138 < a54ffce4637acb0db8e695188a6c7f99f14c3576affected
LinuxLinux6.3affected
LinuxLinux0 < 6.3unaffected
LinuxLinux6.6.157 <= 6.6.*unaffected
LinuxLinux6.12.110 <= 6.12.*unaffected
LinuxLinux6.18.51 <= 6.18.*unaffected
LinuxLinux7.2.5 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References