Threats / Microsoft / CVE-2015-1635
CVE-2015-1635
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-16
Microsoft HTTP.sys vulnerability
Microsoft HTTP.sys remote code execution vulnerability allowing unauthenticated attackers to execute arbitrary code on affected systems through malformed HTTP requests.
Verdict
Today item — known-exploited.
CVE-2015-1635 is a critical remote code execution flaw in HTTP.sys exploited in the wild. The CWE-94 classification indicates improper control of generation of code, enabling attackers to achieve code execution without authentication or user interaction.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
11 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-02-10).
Probability (EPSS)
EPSS 0.99999 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, HTTP.sys. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-94 Code Injection — weakness family: Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No threat-actor attribution is established from the public feed for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malformed HTTP request targeting the vulnerable HTTP.sys parser to trigger code execution.
Business
Unpatched Windows servers become entry points for complete system compromise and data exfiltration.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I deliver the exploit remotely over the network to any exposed HTTP.sys service without requiring credentials.
Business
Attack surface expands across internet-facing infrastructure, multiplying breach risk across web servers and services.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistent access and lateral movement within the compromised network environment.
Business
Incident response costs escalate as attackers move through internal systems, requiring forensics and containment across multiple assets.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by microsoftCNA
Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.