Microsoft WinVerifyTrust function Remote Code Execution
CVE-2013-3900 is a security vulnerability in Microsoft WinVerifyTrust function, added to CISA KEV on January 10, 2022. Patch order: fourth of four.
What is CVE-2013-3900?
A remote code execution vulnerability exists in the way that the WinVerifyTrust function handles Windows Authenticode signature verification for PE files.
VulnCheck tracked exploitation 2722 days before CISA's KEV listing. VulnCheck's broader catalog of in-the-wild exploitation evidence picked this up before it landed on CISA's formal list. Per-CVE fact about this entry; not a population claim about lead time in general.
Who is affected by CVE-2013-3900?
Affects anyone running Microsoft WinVerifyTrust function. Microsoft products in a small practice typically sit close to credentials, email, or document workflows — treat the patch as in-scope.
What should I do about CVE-2013-3900?
Apply updates per vendor instructions.
If you don't have someone in-house to verify the patch deployed across every endpoint — or you're not sure whether you're affected — that's exactly the kind of triage we do. Talk with us.
Insurance readiness
Your insurer will ask if this is patched.
Unpatched entries on CISA's Known Exploited Vulnerabilities list are exactly what cyber-insurance carrier questionnaires probe for, and knowing which controls they check is how you keep a renewal from stalling.
Get the free carrier questionnaire →Severity
CVSS base score: 5.5 — MEDIUM
Weakness classification: CWE-347
Microsoft fix
No fixing KB is published yet in the Microsoft Security Update Guide for this CVE. Check Microsoft's advisory page directly if you need to verify whether an update has shipped.
Microsoft Exploitability Index (assessed at update release): Exploitation Detected
Microsoft has confirmed in-the-wild exploitation in the latest software release. This aligns with CISA's listing of this CVE.
Vendor workaround
No vendor workaround published. Patching is the only fix.
CISA due date
CISA's listed due date: July 10, 2022.
Federal civilian agencies work under CISA's Binding Operational Directive 26-04, which replaced BOD 22-01 on June 10, 2026. It sets the deadline for each affected system by:
- How exposed that system is to the internet
- Whether the attack can be automated
- How much control it gives an attacker
Its table gives catalogued vulnerabilities 3 or 14 days.
None of this binds a private business, but treat the date as a strong recommendation, especially if you handle regulated data (HIPAA, GLBA, ABA model rules).
EPSS
EPSS score: 44.6% — higher than 99% of all scored CVEs.
EPSS estimates the probability of exploitation activity in the next 30 days. Every entry on this site is already confirmed exploited, so read it as relative urgency among the things you still have open, not as permission to wait.
Source
This entry comes from CISA's Known Exploited Vulnerabilities catalog, public US-Government data we pull daily. The plain-language framing and the what-to-do guidance above are ours. View the original entry on cisa.gov.