Use After Free Affecting perf-debuginfo package, versions <0:4.14.262-135.489.amzn1


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.26% (18th percentile)

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  • Snyk IDSNYK-AMZN201803-PERFDEBUGINFO-8688863
  • published6 Feb 2025
  • disclosed24 May 2024

Introduced: 24 May 2024

CVE-2021-47506  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2018.03 perf-debuginfo to version 0:4.14.262-135.489.amzn1 or higher.
This issue was patched in ALAS-2022-1563.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf-debuginfo package and not the perf-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2018.03 relevant fixed versions and status.

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

nfsd: fix use-after-free due to delegation race

A delegation break could arrive as soon as we've called vfs_setlease. A delegation break runs a callback which immediately (in nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we then exit nfs4_set_delegation without hashing the delegation, it will be freed as soon as the callback is done with it, without ever being removed from del_recall_lru.

Symptoms show up later as use-after-free or list corruption warnings, usually in the laundromat thread.

I suspect aba2072f4523 "nfsd: grant read delegations to clients holding writes" made this bug easier to hit, but I looked as far back as v3.0 and it looks to me it already had the same problem. So I'm not sure where the bug was introduced; it may have been there from the beginning.

CVSS Base Scores

version 3.1