Improper Input Validation Affecting bpftool6.18-debuginfo package, versions <1:6.18.54-121.166.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.18% (8th percentile)

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  • Snyk IDSNYK-AMZN2023-BPFTOOL618DEBUGINFO-21426642
  • published22 Oct 2026
  • disclosed6 Oct 2026

Introduced: 6 Oct 2026

NewCVE-2026-98255  (opens in a new tab)
CWE-20  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 bpftool6.18-debuginfo to version 1:6.18.54-121.166.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3192.

NVD Description

Note: Versions mentioned in the description apply only to the upstream bpftool6.18-debuginfo package and not the bpftool6.18-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:

tcp: exclude old ACKs from tcp fast path

Exclude old ACKs before SND.UNA from the tcp fast path as well as ACKs after SND.NXT.

Such ACKs will fall through to the slow path, where tcp_ack() performs the appropriate validation and challenge ACK handling according to RFC5961 and Commit 3d501dd326fb1c7 ("tcp: do not accept ACK of bytes we never sent").

This prevents old ACKs from being accepted or modifying connection state as part of the fast path before appropriate ACK validation is applied. In particular, this prevents payload carried by a segment with an excessively old ACK from advancing RCV.NXT before the ACK is rejected.

CVSS Base Scores

version 3.1