CVE-2026-53239: xfrm: policy: fix use-after-free on inexact bin in xfrm_policy_bysel_ctx()

highCVSS 7CVE-2026-53239

CSIRTS triage

vendor: null product: nullOther

What: A use-after-free vulnerability exists in xfrm_policy_bysel_ctx().
Who is affected: Users of the xfrm policy are affected by this vulnerability.
Urgency: High urgency for remediation due to the potential for exploitation.
Action: Apply the patch for the use-after-free vulnerability.

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
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-53239

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-2026-532390.13% 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-2026-53239	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 Microsoft Azure Linux (June 29, 2026)cert-fr-avis

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-2026-64579: xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsertmsrc · 2026-08-11