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VulnerabilityPublished Updated

CVE-2026-43042: Linux kernel · mpls: add seqcount to protect the platform_label{,s} pair

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High · fixed in 629ec78ef8608d955ce217880cdc3e1873af3a15 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in 629ec78ef8608d955ce217880cdc3e1873af3a15, 8adc5b6fc876928d8c95555d30b66fa50b07421e, 5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade Linux kernel to 629ec78ef8608d955ce217880cdc3e1873af3a15, 8adc5b6fc876928d8c95555d30b66fa50b07421e, 5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef or 0d377825548fe598595b5a5fa4a309fb593d8fb4.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 7720c01f3f590116882e251f13c7e1d5602f8643, < 629ec78ef8608d955ce217880cdc3e1873af3a15
Fixed in
  • 629ec78ef8608d955ce217880cdc3e1873af3a15
LinuxLinuxAffected
  • ≥ 7720c01f3f590116882e251f13c7e1d5602f8643, < 8adc5b6fc876928d8c95555d30b66fa50b07421e
Fixed in
  • 8adc5b6fc876928d8c95555d30b66fa50b07421e
LinuxLinuxAffected
  • ≥ 7720c01f3f590116882e251f13c7e1d5602f8643, < 5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef
Fixed in
  • 5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef
LinuxLinuxAffected
  • ≥ 7720c01f3f590116882e251f13c7e1d5602f8643, < 0d377825548fe598595b5a5fa4a309fb593d8fb4
Fixed in
  • 0d377825548fe598595b5a5fa4a309fb593d8fb4
LinuxLinuxAffected
  • =4.1
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: mpls: add seqcount to protect the platform_label{,s} pair The RCU-protected codepaths (mpls_forward, mpls_dump_routes) can have an inconsistent view of platform_labels vs platform_label in case of a concurrent resize (resize_platform_label_table, under platform_mutex). This can lead to OOB accesses. This patch adds a seqcount, so that we get a consistent snapshot. Note that mpls_label_ok is also susceptible to this, so the check against RTA_DST in rtm_to_route_config, done outside platform_mutex, is not sufficient. This value gets passed to mpls_label_ok once more in both mpls_route_add and mpls_route_del, so there is no issue, but that additional check must not be removed.

References

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