# CVE-2025-68809: ksmbd: vfs: fix race on m_flags in vfs_cache

CVE-2025-68809 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-68809, released January 13, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-68809
- Priority: High
- CVSS: 9.1 (Moderate)
- EPSS: 0.0053
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jan 13, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-68809

## Description

In the Linux kernel, the following vulnerability has been resolved:  ksmbd: vfs: fix race on m_flags in vfs_cache  ksmbd maintains delete-on-close and pending-delete state in ksmbd_inode->m_flags. In vfs_cache.c this field is accessed under inconsistent locking: some paths read and modify m_flags under ci->m_lock while others do so without taking the lock at all.  Examples:   - ksmbd_query_inode_status() and __ksmbd_inode_close() use    ci->m_lock when checking or updating m_flags.  - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),    ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close()    used to read and modify m_flags without ci->m_lock.  This creates a potential data race on m_flags when multiple threads open, close and delete the same file concurrently. In the worst case delete-on-close and pending-delete bits can be lost or observed in an inconsistent state, leading to confusing delete semantics (files that stay on disk after delete-on-close, or files that disappear while still in use).  Fix it by:   - Making ksmbd_query_inode_status() look at m_flags under ci->m_lock    after dropping inode_hash_lock.  - Adding ci->m_lock protection to all helpers that read or modify    m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),    ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).  - Keeping the existing ci->m_lock protection in __ksmbd_inode_close(),    and moving the actual unlink/xattr removal outside the lock.  This unifies the locking around m_flags and removes the data race while preserving the existing delete-on-close behaviour.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.69-1 | [DEBIAN-CVE-2025-68809](https://patchblox.com/security/data/fix/linux/debian-cve-2025-68809.md) | Jan 13, 2026 |
| Linux | linux Debian 14 | 6.18.3-1 | [DEBIAN-CVE-2025-68809](https://patchblox.com/security/data/fix/linux/debian-cve-2025-68809.md) | Jan 13, 2026 |

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Data as of 2026-11-08T00:53:09Z 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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