Improper Update of Reference Count Affecting kernel6.12-debuginfo package, versions <1:6.12.111-136.204.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.21% (10th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNEL612DEBUGINFO-20858366
  • published13 Oct 2026
  • disclosed25 Sept 2026

Introduced: 25 Sep 2026

NewCVE-2026-97556  (opens in a new tab)
CWE-911  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel6.12-debuginfo to version 1:6.12.111-136.204.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3193.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel6.12-debuginfo package and not the kernel6.12-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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

smb: client: avoid leaking refcount when cifs_sb_tlink() fails

cifs_oplock_break() takes over the reference that cifs_queue_oplock_break() acquired when it queued the work, and drops it with _cifsFileInfo_put() once the break has been processed.

Only in setups with "-o multiuser", cifs_sb_tlink() may fail, at which point cifs_oplock_break() returns without putting the file reference, mirroring the reference leak we already fixed in the companion patch to cifs_queue_oplock_break().

This would trigger a crash due to busy inodes on the next unmount:

BUG: Dentry ... still in use (1) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs)

Drop the reference on that path as well. Doing so before the out label mirrors the normal path, which also puts the reference before cifs_done_oplock_break().

Found by Sashiko code review. The failure path was not exercised at runtime.

CVSS Base Scores

version 3.1