CVE-2025-39848 Affecting kernel-libbpf package, versions <1:6.1.153-175.280.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.03% (9th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNELLIBBPF-13170883
  • published1 Oct 2025
  • disclosed19 Sept 2025

Introduced: 19 Sep 2025

NewCVE-2025-39848  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel-libbpf to version 1:6.1.153-175.280.amzn2023 or higher.
This issue was patched in ALAS2023-2025-1210.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-libbpf package and not the kernel-libbpf 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:

ax25: properly unshare skbs in ax25_kiss_rcv()

Bernard Pidoux reported a regression apparently caused by commit c353e8983e0d ("net: introduce per netns packet chains").

skb->dev becomes NULL and we crash in __netif_receive_skb_core().

Before above commit, different kind of bugs or corruptions could happen without a major crash.

But the root cause is that ax25_kiss_rcv() can queue/mangle input skb without checking if this skb is shared or not.

Many thanks to Bernard Pidoux for his help, diagnosis and tests.

We had a similar issue years ago fixed with commit 7aaed57c5c28 ("phonet: properly unshare skbs in phonet_rcv()").

CVSS Base Scores

version 3.1