How severe is CVE-2015-1635?

CVE-2015-1635 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2015-1635?

Affected package information for CVE-2015-1635 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2015-1635?

No fixed version has been published for CVE-2015-1635 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2015-1635 actively exploited in the wild?

Yes. There are 15 known exploit references for CVE-2015-1635, including 2 documented proof-of-concept exploits on Exploit-DB and 10 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

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

CVE-2015-1635 has an EPSS (Exploit Prediction Scoring System) score of 94.3%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2015-1635 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2015-1635 (Microsoft HTTP.sys Remote Code Execution Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2022-02-10. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-08-10. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2015-1635?

CVE-2015-1635 is classified as Code Injection (CWE-94). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Which products and versions are affected by CVE-2015-1635?

CVE-2015-1635 affects microsoft windows 7; microsoft windows 8; microsoft windows 8.1; microsoft windows server 2008 (1 version, e.g. r2), and 1 more product(s). Check the affected-products list on this page against your deployed version to confirm exposure.

Is there exploit tooling available for CVE-2015-1635?

A Nuclei detection template exists for CVE-2015-1635, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2015-1635 published, and has it been updated?

CVE-2015-1635 was published on April 14, 2015 and was last updated on April 22, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2022-02-10 — agencies required to remediate by 2022-08-10

CVE-2015-1635

CRITICAL

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…

Published

Apr 14, 2015

Updated

Apr 22, 2026

Affected

0 pkgs

Patched

None yet

Exploits

15 known

EPSS Exploitation Probability

via FIRST.org ↗

94.3%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

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."

Affected Products

5 products · 7 configurations

windows 7microsoft

all

windows 8microsoft

all

windows 8.1microsoft

all

windows server 2008microsoft

1 version

windows server 2012microsoft

1 version

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-36776doswindows

Microsoft Windows - 'HTTP.sys' HTTP Request Parsing Denial of Service (MS15-034)

by laurent gaffie · Apr 16, 2015

Exploit-DB Source

EDB-36773doswindows

Microsoft Windows - 'HTTP.sys' (PoC) (MS15-034)

by rhcp011235 · Apr 15, 2015

Exploit-DB Source

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2015-1635 in your stack?

O3 detects CVE-2015-1635 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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CVSS Score

9.8/10

CVSS v3 base score

Vector breakdown

AV:Attack Vector

Network

AC:Attack Complexity

Low

PR:Privileges Required

None

UI:User Interaction

None

S:Scope

Unchanged

C:Confidentiality

High

I:Integrity

High

A:Availability

High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE Classification

Weaponization

Timeline

Disclosed

Apr 14, 2015

First exploit

Apr 16, 2015

1 day after disclosure — rapid exploitation

KEV added

Feb 10, 2022

Last updated

Apr 22, 2026

Identifiers

CVE-2015-1635

References

Advisorysecurityfocus.com Advisorysecuritytracker.com Advisorysecurityfocus.com Advisorysecuritytracker.com Fixdocs.microsoft.com Fixdocs.microsoft.com Exploit / PoCpacketstormsecurity.com Exploit / PoCexploit-db.com Exploit / PoCexploit-db.com Exploit / PoCpacketstormsecurity.com Exploit / PoCexploit-db.com Exploit / PoCexploit-db.com Webosvdb.org Webosvdb.org Webcisa.gov

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