Time-of-check Time-of-use (TOCTOU) Affecting kernel6.12-headers package, versions <1:6.12.114-139.210.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.13% (3rd percentile)

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  • Snyk IDSNYK-AMZN2023-KERNEL612HEADERS-22396977
  • published10 Nov 2026
  • disclosed22 Aug 2026

Introduced: 22 Aug 2026

CVE-2026-74605  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel6.12-headers to version 1:6.12.114-139.210.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3402.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel6.12-headers package and not the kernel6.12-headers 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:

eventfs: Use children field for rcu head and add memory barriers

When an eventfs inode is freed, it sets ei->is_freed and then uses its ei->list to add it to the srcu link list as the list field is a union with the rcu list head. As the ei->list is used to iterate over an SRCU protected list without taking the eventfs_mutex, there's nothing stopping the iteration over that list to see the ei->rcu instead of the ei->list and it will read a corrupt target.

To fix this, change the union of the rcu list head with the children list. On freeing the eventfs inode, set the is_free and execute a smp_wmb() before adding the eventfs inode to the SRCU list.

On iteration of the ei->children list, at the start, execute a smp_rmb() and then read the is_freed of the ei to see if the children list is still valid. If is_freed is set, then the ei_child read is not valid and the loop should exit immediately.

CVSS Base Scores

version 3.1