# CVE-2025-68266: bfs: Reconstruct file type when loading from disk

CVE-2025-68266 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-68266, released December 16, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-68266
- Priority: High
- CVSS: 7.1 (Important)
- EPSS: 0.0022
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 16, 2025
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-68266

## Description

In the Linux kernel, the following vulnerability has been resolved:  bfs: Reconstruct file type when loading from disk  syzbot is reporting that S_IFMT bits of inode->i_mode can become bogus when the S_IFMT bits of the 32bits "mode" field loaded from disk are corrupted or when the 32bits "attributes" field loaded from disk are corrupted.  A documentation says that BFS uses only lower 9 bits of the "mode" field. But I can't find an explicit explanation that the unused upper 23 bits (especially, the S_IFMT bits) are initialized with 0.  Therefore, ignore the S_IFMT bits of the "mode" field loaded from disk. Also, verify that the value of the "attributes" field loaded from disk is either BFS_VREG or BFS_VDIR (because BFS supports only regular files and the root directory).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.162-1 | [DEBIAN-CVE-2025-68266](https://patchblox.com/security/data/fix/linux/debian-cve-2025-68266.md) | Dec 16, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.12.63-1 | [DEBIAN-CVE-2025-68266](https://patchblox.com/security/data/fix/linux/debian-cve-2025-68266.md) | Dec 16, 2025 |
| Linux | linux Debian 14 | 6.17.12-1 | [DEBIAN-CVE-2025-68266](https://patchblox.com/security/data/fix/linux/debian-cve-2025-68266.md) | Dec 16, 2025 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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