CVE-2013-3918
CVE-2013-3918 is a security flaw in Microsoft Windows, Microsoft’s operating system for PCs and servers. A booby-trapped web page can run an attacker's code through Microsoft Windows. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 6 Oct 2025.[1]
Microsoft Windows is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Microsoft has published a fix or advice.
Description
CISA calls it an out-of-bounds write in Microsoft Windows. In its words: “Microsoft Windows contains an out-of-bounds write vulnerability in the InformationCardSigninHelper Class ActiveX control, icardie.dll. An attacker could exploit the vulnerability by constructing a specially crafted webpage. When a user views the webpage, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the current user. The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization.”[1]
The underlying weakness is out-of-bounds write (CWE-787), in MITRE’s list of common software weaknesses.[2]
It scores 8.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD 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 Windows.
Every device with Microsoft Windows needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 6 Oct 2025, 4,346 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 27 Oct 2025 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 74%. That’s in the top 1% 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 mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”[1]
- Update Microsoft Windows now.On Windows: Settings, Windows Update, Check for updates, then restart. Office updates come the same way, or from any Office app: File, Account, Update Options. Then turn on automatic updates, so the next fix arrives on its own.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 8.8.[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 74%.[4] |
See also
Other Microsoft Windows flaws
- CVE-2026-96951: command injection ·
- CVE-2026-85880: heap-based buffer overflow ·
- CVE-2026-81963: link following ·
- CVE-2008-4250: buffer overflow ·
- CVE-2026-32202: protection mechanism failure ·
- CVE-2025-60710: link following ·
Other out-of-bounds write flaws
- CVE-2026-86950, Apple devices: out-of-bounds write ·
- CVE-2026-53266, Linux Kernel: out-of-bounds write ·
- CVE-2026-87491, Chrome and other Chromium browsers: out of bounds write ·
- CVE-2026-53362, Linux Kernel: unspecified ·
- CVE-2022-0995, Linux Kernel: out-of-bounds write ·
Added the same day
- CVE-2025-61882, Oracle E-Business Suite: unspecified ·
- CVE-2021-43226, Microsoft Windows: privilege escalation ·
- CVE-2021-22555, Linux Kernel: heap out-of-bounds write ·
- CVE-2011-3402, Microsoft Windows: remote code execution ·
- CVE-2010-3962, Microsoft Internet Explorer: uninitialized memory corruption ·
Every Microsoft flaw on CISA’s list · Everything added in October 2025
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Windows Out-of-Bounds Write Vulnerability”. Known Exploited Vulnerabilities Catalog, added 6 Oct 2025.
- ^ National Institute of Standards and Technology. “CVE-2013-3918 Detail”. National Vulnerability Database, published 12 Nov 2013.
- ^ Microsoft. Advisories and fixes: docs.microsoft.com, microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.737, percentile 99.5, 31 Oct 2026.
- CVE Program. “CVE-2013-3918”. 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.