CVE-2026-74597: ip6_tunnel: clear skb2->cb[] in ip6ip6_err()

CSIRTS triage

What

ip6_tunnel fails to clear skb2->cb[] in error handling, causing kernel memory corruption or DoS.

Who is affected

Linux systems with IPv6 tunnel support enabled.

Urgency

High; CVSS 7.4 and potential kernel corruption require urgent patching.

Action

Apply kernel patch or upgrade to a Linux version with the ip6_tunnel cb[] clearing fix.

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

Details

Source

Microsoft Security Response Center (INTL · vendor-psirt · site)

Severity

high — CVSS 7.4

Published

2026-08-11

Exploitation

Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74597

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-2026-745970.51% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 41% of all EPSS-scored CVEs.

Referenced CVEs

Same CVEs, other sources

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

• medium[NEW] [medium] Linux Kernel: Multiple vulnerabilities allow unspecified attackcert-bund
• criticalCVE-2026-74597: In the Linux kernel, the following vulnerability has been resolved: ip6_tunnel: clear skb2->cb…nvd

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