Out-of-bounds Read Affecting kernel-rt-debug package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.38% (31st percentile)

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  • Snyk IDSNYK-RHEL10-KERNELRTDEBUG-19484940
  • published2 Sept 2026
  • disclosed28 Aug 2026

Introduced: 28 Aug 2026

NewCVE-2026-80634  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 kernel-rt-debug.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug package and not the kernel-rt-debug package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

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

netfilter: flowtable: avoid num_encaps underflow on bridge VLAN untag

The DEV_PATH_BR_VLAN_UNTAG case post-decrements info->num_encaps inside WARN_ON_ONCE(). num_encaps is u8, so if it's already 0 the decrement still happens and wraps it to 255. The break only leaves the inner switch -- a later path entry can set info->indev back to a real device, and we end up returning with num_encaps == 255.

nft_dev_forward_path() then walks info.encap[] (size 2) up to num_encaps, which means an OOB stack read and a bogus count copied into the route descriptor.

Should only happen on a malformed bridge path stack, hence the WARN, but worth handling sanely. Move the decrement out of the WARN.

[ While at this, remove the WARN_ON_ONCE since this can only happen with a buggy bridge path stack --pablo ].

CVSS Base Scores

version 3.1