CVE-2025-40158: ipv6: use RCU in ip6_output()

highCVSS 7.1CVE-2025-40158

CSIRTS triage

vendor: Linux product: ipv6 Denial of service Memory corruption

What: Race condition in ip6_output() missing RCU synchronization during packet processing.
Who is affected: IPv6 traffic processing on all Linux systems with concurrent packet handling.
Urgency: High priority; use-after-free can cause kernel crash or memory corruption under network load.
Action: Apply kernel patch to use RCU protection in ip6_output().

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-2025-40158

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-2025-401580.44% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 36% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2025-40158	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[UPDATE] [high] Linux Kernel: Multiple vulnerabilitiescert-bund
high[UPDATE] [high] IBM QRadar SIEM: Multiple vulnerabilitiescert-bund

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