Cyber Resilience

CVE-2026-2636

Published
25 February 2026
Modified
15 April 2026
CVSS Score v3.1 5.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0041 34th percentile
Risk Priority 43 floored blend · peak EPSS

Summary

CVE-2026-2636 is a medium-severity Improper Handling of Invalid Use of Special Elements (CWE-159) vulnerability in Fortra (inferred from references). Its CVSS base score is 5.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 34th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-159

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-35536Shared CWE-159
CVE-2025-61984Shared CWE-159
CVE-2025-52884Shared CWE-159
CVE-2024-51500Shared CWE-159
CVE-2026-29106Shared CWE-159

Affected Assets

Fortra
—
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

SI-10 requires validity checks on information inputs, directly stopping improper handling of special elements before they affect behavior or integrity.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly enforce input validation and special-element handling to prevent the weakness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can discover the weakness but does not itself implement the preventive control.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and sanitization that directly prevents improper handling of special elements.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for controls against malformed or malicious input.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles reduce attack surface but do not prescribe specific input-filtering techniques.

A.8.28 Secure coding partial match
prevents

Secure coding standards require proper escaping, quoting and validation of special characters in user input.

References