CVE-2026-63817

f2fs: validate compress cache inode only when enabled

State: Published
Severity: 7.8 High
Published: Jul 19, 2026
Updated: Aug 17, 2026
Reserved: Jul 19, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

f2fs: validate compress cache inode only when enabled

F2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is enabled.

When compress_cache is disabled, max_nid is outside the valid inode range. A corrupted directory entry that points to ino == max_nid should therefore be rejected by f2fs_check_nid_range(). However, is_meta_ino() currently treats F2FS_COMPRESS_INO() as a meta inode unconditionally, so f2fs_iget() bypasses do_read_inode() and its nid range check, and instantiates a fake internal inode instead.

Gate the compressed cache inode case on COMPRESS_CACHE, matching f2fs_init_compress_inode(). With compress_cache disabled, ino == max_nid now follows the normal inode path and is rejected as an out-of-range nid.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	6ce19aff0b8cd386860855185c6cd79337fc4d2b to before fcc051d377a9701a452e7663a1a8223c26225df9Affected 6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 29115b8c9172d34e67ab26cc4f6c209b7a236d7aAffected 6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 13e4b59d3a9413f66f116fa6c4828519b960a5eaAffected 6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 16161444c30d8dff9428abbae42b72ce4e32a932Affected 6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 77f216ff9ce5cde8eed9f6d12707e906dffdc9f7Affected 6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 0969926d987bbde9a1aa49da317582ba37095805Affected 6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 5073c66a96a9c23c0c2533ed4ed06e42f9021208Affected a23706426da9b611be5beae0f3faa260fb453b4eAffected 5.13.19 to before 5.14Affected
LinuxLinux	5.14Affected before 5.14Not affected 5.15.212 through 5.15.Not affected 6.1.177 through 6.1.Not affected 6.6.144 through 6.6.Not affected 6.12.95 through 6.12.Not affected 6.18.38 through 6.18.Not affected 7.1.3 through 7.1.Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

6ce19aff0b8cd386860855185c6cd79337fc4d2b to before fcc051d377a9701a452e7663a1a8223c26225df9Affected
6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 29115b8c9172d34e67ab26cc4f6c209b7a236d7aAffected
6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 13e4b59d3a9413f66f116fa6c4828519b960a5eaAffected
6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 16161444c30d8dff9428abbae42b72ce4e32a932Affected
6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 77f216ff9ce5cde8eed9f6d12707e906dffdc9f7Affected
6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 0969926d987bbde9a1aa49da317582ba37095805Affected
6ce19aff0b8cd386860855185c6cd79337fc4d2b to before 5073c66a96a9c23c0c2533ed4ed06e42f9021208Affected
a23706426da9b611be5beae0f3faa260fb453b4eAffected
5.13.19 to before 5.14Affected

LinuxLinux

5.14Affected
before 5.14Not affected
5.15.212 through 5.15.*Not affected
6.1.177 through 6.1.*Not affected
6.6.144 through 6.6.*Not affected
6.12.95 through 6.12.*Not affected
6.18.38 through 6.18.*Not affected
7.1.3 through 7.1.*Not affected
7.2 and laterNot affected

References

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