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.
Affected versions
Linux kernel versions
6.3
and later are affected. Fixed in
6.6.157,
6.12.110,
6.18.51,
7.2.5,
7.3-rc1
and their respective stable series.
References
5 totalFrequently asked questions
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What is CVE-2026-89839?
CVE-2026-89839 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.3 onward and has been patched in 6.6.157, 6.12.110, 6.18.51 and others. CVE-2026-89839 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-89839?
Yes. CVE-2026-89839 has been patched. Fixed versions include 6.6.157, 6.12.110, 6.18.51 and others. If you are running Linux kernel 6.3 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-89839 actively exploited?
No. CVE-2026-89839 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.