CVE-2026-64531: net: openvswitch: reject oversized nested action attrs

mediumpublic exploitCVSS 4.4CVE-2026-64531

CSIRTS triage

vendor: Linux product: Linux kernel Denial of service

What: OpenVswitch incorrectly processes oversized nested action attributes, allowing denial of service or potential code execution.
Who is affected: Linux systems running OpenVswitch with network policy or flow rules accepting untrusted attribute data.
Urgency: Medium severity (CVSS 4.4) primarily causing denial of service; not currently exploited.
Action: Apply Linux kernel patch rejecting oversized nested action attributes in OpenVswitch.

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 4.4
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64531

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-2026-645310.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-64531	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

unknownMultiple vulnerabilities in Debian LTS Linux kernel (August 07, 2026)cert-fr-avis
unknownMultiple vulnerabilities in Debian Linux kernel (August 07, 2026)cert-fr-avis
unknownMultiple vulnerabilities in Red Hat Linux kernel (August 07, 2026)cert-fr-avis
unknownDSA-6405-1 linux - security updatedebian
highCVE-2026-64531: In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reject o…nvd

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