CVE-2026-80847 Affecting kernel-azure-vdso package, versions <6.12.0-160000.39.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.17% (7th percentile)

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  • Snyk IDSNYK-SLES1600-KERNELAZUREVDSO-21353544
  • published21 Oct 2026
  • disclosed12 Oct 2026

Introduced: 12 Oct 2026

NewCVE-2026-80847  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 kernel-azure-vdso to version 6.12.0-160000.39.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-azure-vdso package and not the kernel-azure-vdso package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

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

tcp: clamp route advmss to TCP_MIN_MSS

tcp_select_initial_window() assumes that callers never pass an MSS smaller than 1, but route-derived advmss values can violate that assumption.

A too-small explicit RTAX_ADVMSS is one way to get there, but it is not the only one. The same divide-by-zero can also be reached through the "default advmss" path when RTAX_ADVMSS is left at 0 and the effective advmss is later driven down by route MTU and min_adv_mss.

Introduce a tcp_dst_advmss() helper that clamps route advmss to TCP_MIN_MSS before TCP consumes it, and use it in the TCP paths that derive advmss from dst metrics. This keeps the effective MSS from dropping to zero before tcp_select_initial_window() rounds the receive window.

CVSS Base Scores

version 3.1