CVE-2026-88092Network attack vectorHinoki check available

Unauthenticated tampering via HTTP request smuggling

Published Oct 13, 2026 · Updated Oct 13, 2026

HTTP request smuggling in Microsoft ASP.NET Core allows remote attackers to tamper with application traffic via network requests. The retrieved CNA record identifies inconsistent HTTP request interpretation but does not disclose the faulty parser, malformed input, or exact wrong operation. Authentication and user interaction are not required; the retrieved evidence does not establish a required proxy configuration or the specific data altered.

CVSS severity9.4
Critical
EPSS probability0.79%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
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Summary

What happened

HTTP request smuggling in Microsoft ASP.NET Core allows remote attackers to tamper with application traffic via network requests. The retrieved CNA record identifies inconsistent HTTP request interpretation but does not disclose the faulty parser, malformed input, or exact wrong operation. Authentication and user interaction are not required; the retrieved evidence does not establish a required proxy configuration or the specific data altered.

The record

CVE
CVE-2026-88092
Published
Oct 13, 2026
Updated
Oct 13, 2026
Vendor
Microsoft Corporation
Product
ASP.NET Core 8.0
Classifications
CWE-444
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.0 <8.0.32

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft Corporation · ASP.NET Core 8.0version=8.0 <8.0.32
Microsoft Corporation · ASP.NET Core 9.0version=9.0 <9.0.21
Microsoft Corporation · Microsoft Visual Studio 2022 version 17.14version=17.14.0 <17.14.42
Microsoft Corporation · Microsoft Visual Studioversion=18.10.0 <18.10.4
Microsoft Corporation · ASP.NET Core 11.0version=11.0 <11.0.0-rc.2
Microsoft Corporation · ASP.NET Core 10.0version=10.0 <10.0.13

Published CVSS scores

9.4MicrosoftCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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