Use After Free Affecting kernel-rt-debug package, versions <0:5.14.0-427.35.1.el9_4


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-RHEL9-KERNELRTDEBUG-8469320
  • published5 Dec 2024
  • disclosed13 Mar 2024

Introduced: 13 Mar 2024

CVE-2024-26630  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade RHEL:9 kernel-rt-debug to version 0:5.14.0-427.35.1.el9_4 or higher.
This issue was patched in RHSA-2024:6567.

NVD Description

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

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

mm: cachestat: fix folio read-after-free in cache walk

In cachestat, we access the folio from the page cache's xarray to compute its page offset, and check for its dirty and writeback flags. However, we do not hold a reference to the folio before performing these actions, which means the folio can concurrently be released and reused as another folio/page/slab.

Get around this altogether by just using xarray's existing machinery for the folio page offsets and dirty/writeback states.

This changes behavior for tmpfs files to now always report zeroes in their dirty and writeback counters. This is okay as tmpfs doesn't follow conventional writeback cache behavior: its pages get "cleaned" during swapout, after which they're no longer resident etc.

CVSS Scores

version 3.1