CVE-2013-3900
CVE-2013-3900 is a security flaw in Microsoft WinVerifyTrust function. Attackers can run their own code on Microsoft WinVerifyTrust function. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 10 Jan 2022.[1]
Microsoft WinVerifyTrust function is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Microsoft has published a fix or advice.
Description
CISA calls it a remote code execution in Microsoft WinVerifyTrust function. In its words: “A remote code execution vulnerability exists in the way that the WinVerifyTrust function handles Windows Authenticode signature verification for PE files.”[1]
The CVE record adds: “Why is Microsoft republishing a CVE from 2013? We are republishing CVE-2013-3900 in the Security Update Guide to update the Security Updates table and to inform customers that the EnableCertPaddingCheck is available in all currently supported versions of Windows 10 and Windows 11. While the format is different from the original CVE published in 2013, except for clarifications about how to configure the EnableCertPaddingCheck registry value, the information herein remains unchanged from the original text published on December 10, 2013, Microsoft does not plan to enforce the stricter verification behavior as a default functionality on supported releases of Microsoft Windows. This behavior remains available as an opt-in feature via reg key setting, and is available on supported editions of Windows released since December 10, 2013. This includes all currently supported…”[2]
The underlying weakness is improper input validation (CWE-20), in MITRE’s list of common software weaknesses.
It scores 5.5 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Microsoft’s advisory has them[3]. CISA names the product as Microsoft WinVerifyTrust function.
Most families won’t have Microsoft WinVerifyTrust function; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 10 Jan 2022, 2,952 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 10 Jul 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 45%. That’s in the top 2% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Microsoft has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Microsoft WinVerifyTrust function is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 10 Jul 2022 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 5.5.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 45%.[4] |
See also
Other Microsoft flaws
- CVE-2026-96951, Microsoft Windows: command injection ·
- CVE-2026-65660, Microsoft SharePoint: code injection ·
- CVE-2026-85880, Microsoft Windows: heap-based buffer overflow ·
- CVE-2026-81963, Microsoft Windows: link following ·
- CVE-2019-1068, Microsoft SQL Server: remote code execution ·
Other improper input validation flaws
- CVE-2026-93952, Arista VeloCloud Orchestrator: improper input validation ·
- CVE-2026-12569, PTC Windchill and FlexPLM: improper input validation ·
- CVE-2026-34910, Ubiquiti UniFi OS: improper input validation ·
- CVE-2026-6973, Ivanti Endpoint Manager Mobile (EPMM): improper input validation ·
- CVE-2026-34197, Apache ActiveMQ: improper input validation ·
Added the same day
- CVE-2021-36260, Hikvision Security cameras web server: improper input validation ·
- CVE-2021-27860, FatPipe WARP, IPVPN, and MPVPN software: WARP, IPVPN, and MPVPN configuration upload exploit ·
- CVE-2021-22017, VMware vCenter Server: improper access control ·
- CVE-2020-6572, Google Chrome Media: use-after-free ·
- CVE-2019-9670, Synacor Zimbra Collaboration Suite (ZCS): improper restriction of XML external entity reference ·
Every Microsoft flaw on CISA’s list · Everything added in January 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft WinVerifyTrust function Remote Code Execution”. Known Exploited Vulnerabilities Catalog, added 10 Jan 2022.
- ^ National Institute of Standards and Technology. “CVE-2013-3900 Detail”. National Vulnerability Database, published 11 Dec 2013.
- ^ Microsoft. Advisories and fixes: msrc.microsoft.com, docs.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.446, percentile 98.8, 31 Oct 2026.
- CVE Program. “CVE-2013-3900”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.