CVE-2026-80840: ipv6: seg6: clear IPv4 control block on IPIP decapsulation

Details

Source

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

Severity

high — CVSS 7.4

Published

2026-09-08

Exploitation

Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-80840

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-2026-808400.21% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 11% of all EPSS-scored CVEs.

Referenced CVEs

Same CVEs, other sources

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

• unknownCVE-2026-80840: In the Linux kernel, the following vulnerability has been resolved: ipv6: seg6: clear IPv4 con…nvd

Recent advisories for ipv6

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-2026-89564: In the Linux kernel, the following vulnerability has been resolved: ip: orphan prefetched skbs…nvd · 2026-09-11
• unknownCVE-2026-89561: In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: fix NULL derefe…nvd · 2026-09-11
• unknownCVE-2026-80976: In the Linux kernel, the following vulnerability has been resolved: seg6: reset IP6CB after IP…nvd · 2026-09-11
• lowGHSA-p2w3-6x73-2f6x: Dozzle: SSRF guard bypass via IPv6 transition addresses (6to4/NAT64/Teredo) in webhook no…ghsa · 2026-09-08
• mediumCVE-2026-86735: snipe-it versions before 8.7.0 contain a server-side request forgery vulnerability in the Exte…nvd · 2026-09-08
• criticalCVE-2026-85508: ipmi-oem in FreeIPMI before 1.6.19 has a stack-based buffer overflow in _output_dell_system_in…msrc · 2026-09-08

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