CVE-2026-74696: tcp: fix TFO max_qlen accounting across reuseport migration

mediumCVSS 5.9CVE-2026-74696

CSIRTS triage

vendor: Linux product: Linux kernel Denial of service

What: TCP Fast Open max_qlen accounting fails across reuseport migration, allowing resource exhaustion.
Who is affected: Linux systems with TCP Fast Open and reuseport enabled.
Urgency: Medium priority; not currently exploited but affects availability.
Action: Apply kernel patch for tcp TFO accounting 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: medium — CVSS 5.9
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74696

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-2026-746960.49% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 40% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-74696	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

highCVE-2026-74696: In the Linux kernel, the following vulnerability has been resolved: tcp: fix TFO max_qlen acco…nvd

Recent advisories for tcp

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.

highCVE-2026-74714: In the Linux kernel, the following vulnerability has been resolved: bpf: tcp: Fix use-after-fr…nvd · 2026-08-22
highCVE-2026-74696: In the Linux kernel, the following vulnerability has been resolved: tcp: fix TFO max_qlen acco…nvd · 2026-08-22
highCVE-2026-74624: In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: d…nvd · 2026-08-22
unknownCVE-2026-64773: An attacker that can reach a container's published TCP port may be able to force the host's fo…nvd · 2026-08-20
unknownIssue with FreeRTOS-Plus-TCP - IPv6 Router Advertisement Memory Safety Issuesaws · 2026-08-20
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