CVE-2026-74480: net: bridge: stop fast-leave after deleting a port group

highCVSS 7.5CVE-2026-74480

CSIRTS triage

vendor: Linux product: Linux Kernel Denial of service

What: The bridge fast-leave function continues processing after a port group is deleted, causing denial of service.
Who is affected: Networked systems using Linux bridge with multicast fast-leave enabled on affected kernel versions.
Urgency: High priority; DoS condition is achievable and affects network availability, CVSS 7.5.
Action: Apply kernel patch to stop fast-leave after port group deletion or update to a patched kernel version immediately.

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 7.5
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74480

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-2026-744800.53% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 42% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-74480	coverage & exploitation status	NVD · CVE.org

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criticalCVE-2026-74480: In the Linux kernel, the following vulnerability has been resolved: net: bridge: stop fast-lea…nvd

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