CVE-2026-64579: xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert

mediumCVSS 4.1CVE-2026-64579

CSIRTS triage

vendor: Linux product: Linux Kernel Denial of service

What: A race condition in xfrm policy hash rebuild causes memory allocation failure when reinserting inexact bins without preallocation.
Who is affected: Linux systems using IPsec policy management with xfrm.
Urgency: Medium severity with CVSS 4.1; potential denial of service during policy updates.
Action: Apply kernel patch preallocating inexact bins before xfrm_hash_rebuild or disable dynamic xfrm policy updates.

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 4.1
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64579

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-2026-645790.16% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-64579	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilitiescert-bund
unknownMultiple vulnerabilities in Debian Linux kernel (August 14, 2026)cert-fr-avis
unknownDSA-6415-1 linux - security updatedebian
unknownCVE-2026-64579: In the Linux kernel, the following vulnerability has been resolved: xfrm: policy: preallocate …nvd

Recent advisories for xfrm

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.

criticalCVE-2026-72463: In the Linux kernel, the following vulnerability has been resolved: xfrm: Fix dev use-after-fr…nvd · 2026-08-15
criticalCVE-2026-72451: In the Linux kernel, the following vulnerability has been resolved: xfrm: Fix xfrm state cache…nvd · 2026-08-15
highCVE-2026-72450: In the Linux kernel, the following vulnerability has been resolved: xfrm: validate selector fa…nvd · 2026-08-15
criticalCVE-2026-72137: In the Linux kernel, the following vulnerability has been resolved: xfrm: nat_keepalive: avoid…nvd · 2026-08-15
highCVE-2026-72136: In the Linux kernel, the following vulnerability has been resolved: xfrm: xfrm_interface: requ…nvd · 2026-08-15
mediumCVE-2026-68426: xfrm: fix stale skb->prev after async crypto steals a GSO segmentmsrc · 2026-08-11