Use After Free Affecting linux-6.1 package, versions <6.1.119-1~deb11u1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.04% (5th percentile)

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  • Snyk IDSNYK-DEBIAN11-LINUX61-8601230
  • published2 Jan 2025
  • disclosed21 Oct 2024

Introduced: 21 Oct 2024

CVE-2024-49854  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Debian:11 linux-6.1 to version 6.1.119-1~deb11u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.1 package and not the linux-6.1 package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

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

block, bfq: fix uaf for accessing waker_bfqq after splitting

After commit 42c306ed7233 ("block, bfq: don't break merge chain in bfq_split_bfqq()"), if the current procress is the last holder of bfqq, the bfqq can be freed after bfq_split_bfqq(). Hence recored the bfqq and then access bfqq->waker_bfqq may trigger UAF. What's more, the waker_bfqq may in the merge chain of bfqq, hence just recored waker_bfqq is still not safe.

Fix the problem by adding a helper bfq_waker_bfqq() to check if bfqq->waker_bfqq is in the merge chain, and current procress is the only holder.

CVSS Scores

version 3.1