CVE-2026-2636
MEDIUMDescription
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, allowing an unprivileged user to trigger a system crash. Microsoft silently fixed this vulnerability in the September 2025 cumulative update for Windows 11 2024 LTSC and Windows Server 2025. Windows 25H2 (released in September) was released with the patch. Windows 1123h2 and earlier versions remain vulnerable.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
TridentStack Control tracks known vulnerabilities across your Windows, macOS, and Linux fleet and shows the fix as soon as one is published. See how it works
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 34% of all known CVEs.
References
Related Vulnerabilities
Other CWE-159 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2021-21707 | Medium | 5.3 | 26% | - | Fix |
| CVE-2019-9505 | Critical | 9.8 | 3.5% | - | - |
| CVE-2020-1653 | High | 7.5 | 1.6% | - | - |
| CVE-2020-1648 | High | 7.5 | 1.3% | - | - |
| CVE-2020-1646 | High | 7.5 | 1.0% | - | - |
| CVE-2020-29022 | Medium | 5.3 | 0.8% | - | Fix |
Common questions
How do I fix CVE-2026-2636?
No published fix for CVE-2026-2636 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-2636 being actively exploited?
Not that we know of. CVE-2026-2636 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.41% is the estimated probability that it will be exploited in the next 30 days. That is higher than 34% of all scored CVEs.
How severe is CVE-2026-2636?
CVE-2026-2636 has a CVSS v3 base score of 5.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2026-2636
Markdown
[](https://tridentstack.com/cve/CVE-2026-2636)HTML
<a href="https://tridentstack.com/cve/CVE-2026-2636"><img src="https://tridentstack.com/cve/badge/CVE-2026-2636.svg" alt="CVE-2026-2636"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-27.