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

highCVSS 7.1CVE-2026-43042

CSIRTS triage

vendor: Linux product: mpls Denial of service

What: A race condition in MPLS platform label pair access requires seqcount synchronization.
Who is affected: Systems using MPLS networking in the Linux kernel.
Urgency: High severity (CVSS 7.1) race condition; urgent patching recommended.
Action: Update to the latest kernel version containing the MPLS seqcount synchronization fix.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.1
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-43042

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-430420.11% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 1% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-43042	coverage & exploitation status	NVD · CVE.org

Recent advisories for mpls

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-74577: In the Linux kernel, the following vulnerability has been resolved: net: mpls: initialize rtm_…nvd · 2026-08-15
lowCVE-2026-74577: net: mpls: initialize rtm_tos in mpls_getroute()msrc · 2026-08-11
mediumCVE-2026-64569: mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=nmsrc · 2026-08-11
unknownCVE-2026-64569: In the Linux kernel, the following vulnerability has been resolved: mpls: fix NULL deref in mp…nvd · 2026-08-05