CVE-2026-63818
In the Linux kernel, the following vulnerability has been resolved: f2fs: validate orphan inode entry count f2fs_recover_orphan_inodes() trusts the orphan block entry_count when replaying orphan inodes from the checkpoint pack. A corrupted entry_count larger than F2FS_ORPHANS_PER_BLOCK makes the recovery loop read past the ino[] array and interpret footer or following data as inode numbers. On a crafted image, mounting an unpatched kernel can drive orphan recovery into f2fs_bug_on() and panic the kernel. Validate entry_count before consuming entries so corrupted checkpoint data fails the mount with -EFSCORRUPTED and requests fsck instead. Set ERROR_INCONSISTENT_ORPHAN as well, so the corruption reason can be recorded in the superblock s_errors[] field. This gives fsck a persistent hint even though mount-time orphan recovery failure may leave no chance to persist SBI_NEED_FSCK through a checkpoint.
Affected versions
Linux kernel versions
3.8
and later are affected. Fixed in
6.12.96,
6.18.38,
7.1.3,
7.2-rc1
and their respective stable series.
References
4 totalFrequently asked questions
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What is CVE-2026-63818?
CVE-2026-63818 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 3.8 onward and has been patched in 6.12.96, 6.18.38, 7.1.3 and others. CVE-2026-63818 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-2026-63818?
Yes — CVE-2026-63818 has been patched. Fixed versions include 6.12.96, 6.18.38, 7.1.3 and others. If you are running Linux kernel 3.8 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-63818 actively exploited?
No — CVE-2026-63818 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.