CVE-2013-3918: Microsoft Windows Out-of-Bounds Write Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Microsoft Windows. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-10-06, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-10-27; treat that as the outer limit, not the target.
• EPSS 73.7%, percentile 99: FIRST’s model estimates a 73.7% chance of exploitation activity in the next 30 days, higher than 99% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.

What it is

The InformationCardSigninHelper Class ActiveX control in icardie.dll in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows remote attackers to execute arbitrary code or cause a denial of service (out-of-bounds write) via a crafted web page that is accessed by Internet Explorer, as exploited in the wild in November 2013, aka "InformationCardSigninHelper Vulnerability."

CISA’s summary

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.

Weakness type: CWE-787.

Product: Microsoft Windows · Assigned by: microsoft · Published: 2013-11-12

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: required (a user must click/open something)
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2025-10-06; federal due date 2025-10-27. Known ransomware use: Unknown.
• CISA 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.
• CISA SSVC assessment: exploitation active, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 73.69% probability of exploitation activity in the next 30 days; percentile 99.

Timeline

• 2013-11-12 — CVE record published by microsoft
• 2025-10-06 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2025-10-22 — CVE record last updated
• 2025-10-27 — CISA remediation deadline for US federal agencies

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. MS13-090 docs.microsoft.com
2. microsoft.com microsoft.com

Vulnerability records

1. CVE.org record CVE-2013-3918 cve.org
2. NVD entry CVE-2013-3918 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

Other references from the CVE record and advisory

1. TA13-317A us-cert.gov
2. darkreading.com darkreading.com
3. fireeye.com fireeye.com
4. oval:org.mitre.oval:def:19089 oval.cisecurity.org
5. isc.sans.edu isc.sans.edu
6. blogs.technet.com blogs.technet.com

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