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Review reviewHigh

CVE-2026-63817

Linux

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_ig...

CVSS
7.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.19
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 7.8

Vulnerability overview

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_ig...

Affected product and versions

Product
Linux
Affected versions
>= 6ce19aff0b8cd386860855185c6cd79337fc4d2b < fcc051d377a9701a452e7663a1a8223c26225df9, >= 6ce19aff0b8cd386860855185c6cd79337fc4d2b < 29115b8c9172d34e67ab26cc4f6c209b7a236d7a, >= 6ce19aff0b8cd386860855185c6cd79337fc4d2b < 13e4b59d3a9413f66f116fa6c4828519b960a5ea, >= 6ce19aff0b8cd386860855185c6cd79337fc4d2b < 16161444c30d8dff9428abbae42b72ce4e32a932, >= 6ce19aff0b8cd386860855185c6cd79337fc4d2b < 77f216ff9ce5cde8eed9f6d12707e906dffdc9f7, >= 6ce19aff0b8cd386860855185c6cd79337fc4d2b < 0969926d987bbde9a1aa49da317582ba37095805, >= 6ce19aff0b8cd386860855185c6cd79337fc4d2b < 5073c66a96a9c23c0c2533ed4ed06e42f9021208, >= a23706426da9b611be5beae0f3faa260fb453b4e, >= 5.13.19 < 5.14, >= 5.14
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Not available