Microsoft Windows Protection Mechanism Failure Vulnerability
Microsoft · Windows
CVSS 4.3
EPSS 64%
1 public exploit
Fix deadline passed 12 May 2026
What it is
Microsoft Windows Shell contains a protection mechanism failure vulnerability that allows an unauthorized attacker to perform spoofing over a network.
Why we say that
- EPSS puts exploitation in the next 30 days at 64%
- 1 public exploit published
- CISA's federal remediation deadline (2026-05-12) has passed
- Listed in the CISA Known Exploited Vulnerabilities catalogue
Every line above comes from a named public source. Where the evidence is thin, we say so rather than inventing confidence — see methodology.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Public exploit code
Indexed from Exploit-DB. Presence of code raises urgency; absence does not mean safety.
What it costs when this goes wrong
This is where UK enforcement meets the vulnerability record. Where an unfixed vulnerability leads to a breach, the ICO treats it as a security failure under UK GDPR. Recent cases:
- The Electoral Commission Reprimand issued to the Electoral Commission in respect of Articles 5(1)(f) and 32(1)(b). Between 24 August 2021 and 27 October 20…
- Gain Capital UK Limited Gain Capital UK have been issued a Reprimand in respect of Articles 32 (2) and 32 (1) (b). An unauthorised third party leveraged a…
- Chartered Institute for Securities & Investment An unauthorised third party exploited a known vulnerability in the Sitefinity software to leverage a bruteforce attack to upload a…