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Fencer Vulns
critical 9.1

CVE-2025-68809 in the critical feed json

ksmbd: vfs: fix race on m_flags in vfs_cache

published 2026-01-13 9 mo ago modified 2026-10-30 9 d ago also EUVD-2026-2295

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 6.1.191, 6.6.120, 6.12.64, 6.18.3, 6.19
  • linux Debian 13 6.12.69-1
  • linux Debian 14 6.18.3-1

debian advisories DEBIAN-CVE-2025-68809

  • linux Ubuntu 24.04 LTS 6.8.0-110.110
  • linux Ubuntu 25.10 6.17.0-22.22
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1052.55
  • linux-aws Ubuntu 25.10 6.17.0-1012.12
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1054.57
  • linux-gcp Ubuntu 25.10 6.17.0-1012.12
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1050.56
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1051.51

ubuntu advisories UBUNTU-CVE-2025-68809

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel Azure Linux 3.0 6.6.121.1-1

azure linux advisories AZL-74423

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-68809 updated cvss 9.1

kernel: ksmbd: Remote race condition leads to data integrity issues and denial of service

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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