Integer Overflow or Wraparound Affecting kernel-modules-internal package, versions *


Severity

Recommended
low

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.2% (10th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELMODULESINTERNAL-21031787
  • published16 Oct 2026
  • disclosed17 Sept 2026

Introduced: 17 Sep 2026

NewCVE-2026-90109  (opens in a new tab)
CWE-190  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:8 kernel-modules-internal.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-modules-internal package and not the kernel-modules-internal package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

net: sched: fix 32-bit backlog wrap in gred, bfifo and plug enqueue

gred_enqueue(), bfifo_enqueue() and plug_enqueue() admit a packet when the current backlog plus the packet length fits within the queue limit:

sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit (gred default VQ) gred_backlog+qdisc_pkt_len(skb) <= q->limit (gred configured VQ) sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit (bfifo) sch->qstats.backlog + skb->len <= q->limit (plug)

sch->qstats.backlog and q->backlog are u32, and qdisc_pkt_len()/skb->len are unsigned int, so all sums are computed in 32 bits and wrap at 2^32. Once the true backlog exceeds 4 GiB the wrapped sum becomes small and admission keeps succeeding, so the queue grows without bound and the kernel can be driven to OOM.

Promote the sums to u64 so admission stops once the true backlog exceeds the limit. The limit is u32, so the bounded queue stays below 2^32 and the stored u32 backlog never wraps.

The bug can only be reproduced as root (albeit with ridiculous setup): attach a gred (or bfifo/plug) qdisc with a limit near 4 GiB, leaving the default VQ unconfigured (for gred), and drive >4 GiB of queued traffic (e.g. via a size table / stab to inflate qdisc_pkt_len, or sustained high-rate traffic). The u32 backlog+len sum wraps at 2^32, admission keeps succeeding, and the queue grows unboundedly to OOM.

CVSS Base Scores

version 3.1