CVE-2026-74321 Affecting kernel-default-livepatch package, versions <6.4.0-150700.53.81.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.72% (52nd percentile)

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  • Snyk IDSNYK-SLES157-KERNELDEFAULTLIVEPATCH-19918402
  • published18 Sept 2026
  • disclosed17 Sept 2026

Introduced: 17 Sep 2026

NewCVE-2026-74321  (opens in a new tab)

How to fix?

Upgrade SLES:15.7 kernel-default-livepatch to version 6.4.0-150700.53.81.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-livepatch package and not the kernel-default-livepatch package as distributed by SLES. See How to fix? for SLES:15.7 relevant fixed versions and status.

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

btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs()

In the beginning of the loop, we try to obtain a locked delayed ref head, if 'locked_ref' is currently NULL, by calling btrfs_select_ref_head(), which can return an error pointer. If the error pointer is -EAGAIN we do a continue and go back to the beginning of the loop, which will not try again to call btrfs_select_ref_head() since 'locked_ref' is no longer NULL but it's ERR_PTR(-EAGAIN), and then we do:

spin_lock(&locked_ref->lock);

against a ERR_PTR(-EAGAIN) value, generating an invalid pointer dereference.

Fix this by ensuring that 'locked_ref' is set to NULL when btrfs_select_ref_head() returns ERR_PTR(-EAGAIN) and incrementing 'count' as well, to prevent infinite looping. We do this by doing a goto to the bottom of the loop that already sets 'locked_ref' to NULL and does a cond_resched(), with an increment to 'count' right before the goto. These measures were in place before the refactoring in commit 0110a4c43451 ("btrfs: refactor __btrfs_run_delayed_refs loop") but were unintentionally lost afterwards.

CVSS Base Scores

version 3.1