CVE-2026-53014 Affecting kernel-kvmsmall package, versions <6.12.0-160000.37.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.16% (6th percentile)

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  • Snyk IDSNYK-SLES1600-KERNELKVMSMALL-19320199
  • published27 Aug 2026
  • disclosed11 Aug 2026

Introduced: 11 Aug 2026

NewCVE-2026-53014  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 kernel-kvmsmall to version 6.12.0-160000.37.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-kvmsmall package and not the kernel-kvmsmall 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:

net/sched: act_mirred: fix wrong device for mac_header_xmit check in tcf_blockcast_redir

In tcf_blockcast_redir(), when iterating block ports to redirect packets to multiple devices, the mac_header_xmit flag is queried from the wrong device. The loop sends to dev_prev but queries dev_is_mac_header_xmit(dev) — which is the NEXT device in the iteration, not the one being sent to.

This causes tcf_mirred_to_dev() to make incorrect decisions about whether to push or pull the MAC header. When the block contains mixed device types (e.g., an ethernet veth and a tunnel device), intermediate devices get the wrong mac_header_xmit flag, leading to skb header corruption. In the worst case, skb_push_rcsum with an incorrect mac_len can exhaust headroom and panic.

The last device in the loop is handled correctly (line 365-366 uses dev_is_mac_header_xmit(dev_prev)), confirming this is a copy-paste oversight for the intermediate devices.

Fix by using dev_prev instead of dev for the mac_header_xmit query, consistent with the device actually being sent to.

CVSS Base Scores

version 3.1