Is CVE-2015-1635 being actively exploited?

Yes. CVE-2015-1635 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added on February 10, 2022.

What is the CVSS score for CVE-2015-1635?

CVE-2015-1635 has a CVSS 3.1 base score of 9.8 (CRITICAL).

CVE-2015-1635

CRITICAL · CVSS 9.8CISA KEV: actively exploitedEPSS 100.0%EU EUVD: exploited

HTTP.sys in Microsoft Windows 7 SP1, Windows Server 2008 R2 SP1, Windows 8, Windows 8.1, and Windows Server 2012 Gold and R2 allows remote attackers to execute arbitrary code via crafted HTTP requests, aka "HTTP.sys Remote Code Execution Vulnerability."

Key facts

CVSS score: 9.8 (v3.1)
Severity: CRITICAL
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-94
EPSS score: 100.0% (100th percentile)
In CISA KEV: Yes, added February 10, 2022
In EU EUVD: Yes (EUVD-2015-1765)
Published: April 14, 2015
NVD last modified: June 17, 2026
Status: Analyzed

CISA Known Exploited Vulnerability

Microsoft HTTP.sys Remote Code Execution Vulnerability

Added to the KEV catalog on February 10, 2022; federal remediation due August 10, 2022.

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2015-1765 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on October 22, 2025.

View on the EU Vulnerability Database

Affected products

microsoft / windows 7
microsoft / windows 8
microsoft / windows 8.1
microsoft / windows server 2008
microsoft / windows server 2008
microsoft / windows server 2012
microsoft / windows server 2012

Certified products that may be affected

8 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Microsoft Windows 8 and Windows RT - Microsoft Corporation - Common Criteria CCEVS-VR-VID-10620-2015 - archived
Windows 7 BitLocker™ Drive Encryption - Microsoft Corporation - FIPS 140 1332 - historical
Microsoft Windows 7 Kernel Mode Cryptographic Primitives Library (cng.sys) - Microsoft Corporation - FIPS 140 1328 - historical
Microsoft Windows Vista Kernel Mode Security Support Provider Interface (ksecdd.sys) - Microsoft Corporation - FIPS 140 1000 - historical
Microsoft Windows Vista Cryptographic Primitives Library (bcrypt.dll) - Microsoft Corporation - FIPS 140 1001 - historical

See all 8 in the Security Certifications Explorer.

References

http://packetstormsecurity.com/files/131463/Microsoft-Windows-HTTP.sys-Proof-Of-Concept.html(Exploit, Third Party Advisory, VDB Entry)
http://www.osvdb.org/120629(Broken Link)
http://www.securityfocus.com/bid/74013(Broken Link, Third Party Advisory, VDB Entry)
http://www.securitytracker.com/id/1032109(Broken Link, Third Party Advisory, VDB Entry)
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-034(Patch, Vendor Advisory)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-1635(US Government Resource)
https://www.exploit-db.com/exploits/36773/(Exploit, Third Party Advisory, VDB Entry)
https://www.exploit-db.com/exploits/36776/(Exploit, Third Party Advisory, VDB Entry)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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