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


Severity

Recommended
low

Based on CentOS security rating.

Threat Intelligence

EPSS
0.21% (11th percentile)

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  • Snyk IDSNYK-CENTOS8-KERNELMODULESINTERNAL-21039901
  • published16 Oct 2026
  • disclosed14 Oct 2026

Introduced: 14 Oct 2026

NewCVE-2026-98393  (opens in a new tab)
CWE-190  (opens in a new tab)

How to fix?

There is no fixed version for Centos: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 Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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

net: ipv4: Fix UDP length overflow with PMTU discover and big MTU

This commit bounds cork->base.fragsize to IP_MAX_MTU to avoid a possible overflow of UDP length that triggers a WARN in udp_set_len_short when setsockopt IP_MTU_DISCOVER is set to IP_PMTUDISC_PROBE, and a large packet is sent over a netdev with an unusually large MTU.

Steps to reproduce:

  1. Set device MTU bigger than IP_MAX_MTU + 20. cork->base.fragsize will be set to that MTU in ip_setup_cork.
  2. Set IP_MTU_DISCOVER to IP_PMTUDISC_PROBE. It lets maxnonfragsize be set to device MTU (cork->fragsize) in __ip_append_data, rather than to IP_MAX_MTU.
  3. Send 65528 bytes of payload (+8 bytes of UDP header, +20 bytes of IPv4 header). Device MTU allows it (it's only one byte bigger than IP_MAX_MTU + IPv4 header, and the device MTU is bigger than that).
  4. The UDP length in the built packet is 65536, which overflows the 16-bit length field and triggers the WARN in udp_set_len_short.

Note: IP_PMTUDISC_DO with IPv4 is safe, because ip_dst_mtu_maybe_forward always clamps at IP_MAX_MTU, unlike ip6_dst_mtu_maybe_forward.

The Fixes tag points at the first commit where I could reproduce the overflow with IPv4 and IP_PMTUDISC_PROBE.

CVSS Base Scores

version 3.1