CVE-2026-72502 Affecting kernel-64kb package, versions <6.4.0-150700.53.81.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.72% (52nd percentile)

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  • Snyk IDSNYK-SLES157-KERNEL64KB-19918241
  • published18 Sept 2026
  • disclosed17 Sept 2026

Introduced: 17 Sep 2026

NewCVE-2026-72502  (opens in a new tab)

How to fix?

Upgrade SLES:15.7 kernel-64kb to version 6.4.0-150700.53.81.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-64kb package and not the kernel-64kb package as distributed by SLES. See How to fix? for SLES:15.7 relevant fixed versions and status.

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

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)

When MTU is large, ip6_default_advmss() can return IPV6_MAXPLEN (65535). This is interpreted by TCP as mss_clamp, allowing the MSS to reach 65535.

However, 0xFFFF is also used as a magic value GSO_BY_FRAGS in the kernel. If a TCP packet with gso_size=0xFFFF is passed to skb_segment(), it will be mistakenly treated as GSO_BY_FRAGS, leading to a NULL pointer dereference because local TCP packets do not use frag_list.

Fix this by returning min(IPV6_MAXPLEN, GSO_BY_FRAGS - 1) (65534) from ip6_default_advmss() when MTU is large.

Also update the stale comment in ip6_default_advmss() which suggested that IPV6_MAXPLEN is returned to mean "any MSS".

CVSS Base Scores

version 3.1