CVE-2026-53349: netfilter: nf_conntrack: destroy stale expectfn expectations on unregister

mediumCVSS 5.5CVE-2026-53349

CSIRTS triage

Other

What: There is a vulnerability in nf_conntrack related to stale expectations.
Who is affected: Deployments using netfilter are affected.
Urgency: Remediation is medium urgency due to the potential for exploitation.
Action: Apply relevant patches or updates.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.5
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-53349

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-2026-533490.11% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 2% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-53349	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 LTS Linux kernel (July 10, 2026)cert-fr-avis
unknownMultiple vulnerabilities in Microsoft Azure Linux (July 10, 2026)cert-fr-avis
unknownCVE-2026-53349: In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: d…nvd

Recent advisories for netfilter

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-2026-74695: In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_flow_table: …nvd · 2026-08-22
highCVE-2026-74660: In the Linux kernel, the following vulnerability has been resolved: netfilter: ebt_nflog: pin …nvd · 2026-08-22
highCVE-2026-74625: In the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: release…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-2026-74579: In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_payload: fi…nvd · 2026-08-17
criticalCVE-2026-74569: In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_si…nvd · 2026-08-15