Integer Overflow or Wraparound Affecting kernel-livepatch-6.18.54-121.166 package, versions <1:1.0-0.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.2% (10th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNELLIVEPATCH61854121166-20856429
  • published13 Oct 2026
  • disclosed17 Sept 2026

Introduced: 17 Sep 2026

NewCVE-2026-90076  (opens in a new tab)
CWE-190  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel-livepatch-6.18.54-121.166 to version 1:1.0-0.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3192.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-livepatch-6.18.54-121.166 package and not the kernel-livepatch-6.18.54-121.166 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/sched: fq: add overflow bounds to quantum and initial quantum

fq_init() computes quantum = 2 * psched_mtu() and initial_quantum = 10 * psched_mtu() with no overflow check. A device with a huge MTU (e.g. dummy with max_mtu == 0 accepting MTU 2147483634) makes psched_mtu() return 0x80000000; the 2 * and 10 * multiplications wrap to 0 in 32-bit arithmetic, so q->quantum == 0. Then in fq_dequeue() the credit-refill loop adds 0 to f->credit (which stays <= 0) and goto begin loops forever under the qdisc lock, creating a soft lockup.

Clamp psched_mtu() to [1, 1 << 20] before multiplying so the product cannot wrap, then cap the result at 1 << 20, matching the bound already enforced on TCA_FQ_QUANTUM in fq_change().

Conditions to recreate the bug: a device whose MTU (plus hard_header_len) is large enough that 2 * psched_mtu() wraps (e.g. a dummy device with max_mtu == 0 accepting MTU 2147483634). Requires CAP_NET_ADMIN in a user namespace.

CVSS Base Scores

version 3.1