Expired Pointer Dereference Affecting bpftool-debuginfo package, versions <1:6.1.168-202.320.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.01% (3rd percentile)

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  • Snyk IDSNYK-AMZN2023-BPFTOOLDEBUGINFO-16626766
  • published10 May 2026
  • disclosed25 Apr 2026

Introduced: 25 Apr 2026

NewCVE-2026-31680  (opens in a new tab)
CWE-825  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 bpftool-debuginfo to version 1:6.1.168-202.320.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1681.

NVD Description

Note: Versions mentioned in the description apply only to the upstream bpftool-debuginfo package and not the bpftool-debuginfo 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:

net: ipv6: flowlabel: defer exclusive option free until RCU teardown

ip6fl_seq_show() walks the global flowlabel hash under the seq-file RCU read-side lock and prints fl-&gt;opt-&gt;opt_nflen when an option block is present.

Exclusive flowlabels currently free fl-&gt;opt as soon as fl-&gt;users drops to zero in fl_release(). However, the surrounding struct ip6_flowlabel remains visible in the global hash table until later garbage collection removes it and fl_free_rcu() finally tears it down.

A concurrent /proc/net/ip6_flowlabel reader can therefore race that early kfree() and dereference freed option state, triggering a crash in ip6fl_seq_show().

Fix this by keeping fl-&gt;opt alive until fl_free_rcu(). That matches the lifetime already required for the enclosing flowlabel while readers can still reach it under RCU.

CVSS Base Scores

version 3.1