Missing Release of Resource after Effective Lifetime Affecting kernel6.18-libbpf-debuginfo package, versions <1:6.18.20-20.229.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.01% (4th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNEL618LIBBPFDEBUGINFO-16350155
  • published3 May 2026
  • disclosed25 Mar 2026

Introduced: 25 Mar 2026

CVE-2026-23331  (opens in a new tab)
CWE-772  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel6.18-libbpf-debuginfo to version 1:6.18.20-20.229.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1596.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel6.18-libbpf-debuginfo package and not the kernel6.18-libbpf-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:

udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected.

Let's say we bind() an UDP socket to the wildcard address with a non-zero port, connect() it to an address, and disconnect it from the address.

bind() sets SOCK_BINDPORT_LOCK on sk->sk_userlocks (but not SOCK_BINDADDR_LOCK), and connect() calls udp_lib_hash4() to put the socket into the 4-tuple hash table.

Then, __udp_disconnect() calls sk->sk_prot->rehash(sk).

It computes a new hash based on the wildcard address and moves the socket to a new slot in the 4-tuple hash table, leaving a garbage in the chain that no packet hits.

Let's remove such a socket from 4-tuple hash table when disconnected.

Note that udp_sk(sk)->udp_portaddr_hash needs to be udpated after udp_hash4_dec(hslot2) in udp_unhash4().

CVSS Base Scores

version 3.1