Use After Free Affecting rtla package, versions <0:5.14.0-687.36.1.el9_8


Severity

Recommended
medium

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.13% (4th percentile)

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  • Snyk IDSNYK-ALMALINUX9-RTLA-18591639
  • published8 Aug 2026
  • disclosed6 Aug 2026

Introduced: 6 Aug 2026

NewCVE-2026-23415  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:9 rtla to version 0:5.14.0-687.36.1.el9_8 or higher.
This issue was patched in ALSA-2026:51035.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rtla package and not the rtla package as distributed by AlmaLinux. See How to fix? for AlmaLinux:9 relevant fixed versions and status.

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

futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()

During futex_key_to_node_opt() execution, vma->vm_policy is read under speculative mmap lock and RCU. Concurrently, mbind() may call vma_replace_policy() which frees the old mempolicy immediately via kmem_cache_free().

This creates a race where __futex_key_to_node() dereferences a freed mempolicy pointer, causing a use-after-free read of mpol->mode.

[ 151.412631] BUG: KASAN: slab-use-after-free in __futex_key_to_node (kernel/futex/core.c:349) [ 151.414046] Read of size 2 at addr ffff888001c49634 by task e/87

[ 151.415969] Call Trace:

[ 151.416732] __asan_load2 (mm/kasan/generic.c:271) [ 151.416777] __futex_key_to_node (kernel/futex/core.c:349) [ 151.416822] get_futex_key (kernel/futex/core.c:374 kernel/futex/core.c:386 kernel/futex/core.c:593)

Fix by adding rcu to __mpol_put().

CVSS Base Scores

version 3.1