HTTP.sys Denial of Service Vulnerability
Out-of-bounds read in Windows HTTP.sys allows an unauthorized attacker to deny service over a network.
- Published
- Apr 14, 2026
- Updated
- Sep 25, 2026
- EPSS
- 1.2% · 66th percentile
- CWE
- CWE-125
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · microsoft
- 7.5
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| microsoft | windows 11 23h2 | cpe:2.3:o:microsoft:windows_11_23h2 |
| microsoft | windows 11 24h2 | cpe:2.3:o:microsoft:windows_11_24h2 |
| microsoft | windows 11 25h2 | cpe:2.3:o:microsoft:windows_11_25h2 |
| microsoft | windows 11 26h1 | cpe:2.3:o:microsoft:windows_11_26h1 |
| microsoft | windows server 2022 | cpe:2.3:o:microsoft:windows_server_2022 |
| microsoft | windows server 2022 23h2 | cpe:2.3:o:microsoft:windows_server_2022_23h2 |
| microsoft | windows server 2025 | cpe:2.3:o:microsoft:windows_server_2025 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- microsoft windows server 2022before 10.0.20348.5020
- microsoft windows server 2022 23h2before 10.0.25398.2274
- microsoft windows server 2025before 10.0.26100.32690
Versions reported by the vendor
Affected version ranges reported by the assigning authority (microsoft). Independent of NVD's CPE analysis and usually ahead of it.
Microsoft Windows 11 version 22H3
- 10.0.22631.0 and later · before 10.0.22631.6936affected
Microsoft Windows 11 Version 23H2
- 10.0.22631.0 and later · before 10.0.22631.6936affected
Microsoft Windows 11 Version 24H2
- 10.0.26100.0 and later · before 10.0.26100.8246affected
Microsoft Windows 11 Version 25H2
- 10.0.26200.0 and later · before 10.0.26200.8246affected
Microsoft Windows 11 version 26H1
- 10.0.28000.0 and later · before 10.0.28000.1836affected
Microsoft Windows Server 2022
- 10.0.20348.0 and later · before 10.0.20348.5020affected
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation)
- 10.0.25398.0 and later · before 10.0.25398.2274affected
Microsoft Windows Server 2025
- 10.0.26100.0 and later · before 10.0.26100.32690affected
Microsoft Windows Server 2025 (Server Core installation)
- 10.0.26100.0 and later · before 10.0.26100.32690affected
Same product
microsoft: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-81963Windows Update Stack Elevation of Privilege VulnerabilityKEV61This week
- CVE-2026-62815Microsoft QUIC Remote Code Execution Vulnerability39Monitor
- CVE-2026-45657Windows Kernel Remote Code Execution Vulnerability39Monitor
- CVE-2026-41096Windows DNS Client Remote Code Execution Vulnerability39Monitor
- CVE-2025-9491Microsoft Windows LNK File UI Misrepresentation Remote Code Execution Vulnerability39Monitor
- CVE-2026-40402Windows Hyper-V Elevation of Privilege Vulnerability37Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-320760 days apartWindows Storage Spaces Controller Elevation of Privilege Vulnerability31Monitor
- CVE-2026-70569147 days apartWindows Spaceport.sys Elevation of Privilege Vulnerability31Monitor
- CVE-2026-4560456 days apartWindows Managed Installer Information Disclosure Vulnerability22Monitor
- CVE-2025-62468126 days apartWindows Defender Firewall Service Information Disclosure Vulnerability22Monitor
- CVE-2026-83501147 days apartWindows Virtualization-Based Security (VBS) Information Disclosure Vulnerability22Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-125 · Out-of-bounds ReadCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.