What is CVE-2026-2636?

CVE-2026-2636 is a medium-severity vulnerability in Microsoft Windows Os, classified under CWE-159. CVSS score: 5.5/10. Published 2026-02-25.

How severe is CVE-2026-2636?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Is CVE-2026-2636 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Microsoft Windows Os

CVE-2026-2636

This vulnerability is caused by a CWE‑159: "Improper Handling of Invalid Use of Special Elements" weakness, which leads to an unrecoverable inconsistency in the CLFS.sys driver. This condition forces a call to the KeBugCheckEx function, al…

EPSS: 0.001 (18.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Microsoft Windows Os — versions 0

Weakness classification (CWE)

CWE-159

Public proof-of-concept exploits

References

www.fortra.com/security/advisories/research/fr-2026-001

Frequently asked questions

What is CVE-2026-2636?: CVE-2026-2636 is a medium-severity vulnerability in Microsoft Windows Os, classified under CWE-159. CVSS score: 5.5/10. Published 2026-02-25.
How severe is CVE-2026-2636?: Medium severity. CVSS v3 base score is 5.5 out of 10.
Is CVE-2026-2636 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.