ASP.NET Core 10.0: Inconsistent Interpretation of HTTP Requests
CVE-2026-70188 is a critical-severity inconsistent interpretation of HTTP requests vulnerability in ASP.NET Core 10.0 from Microsoft, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 10.0.13 as the first without the flaw, so updating ASP.NET Core 10.0 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.03% chance of exploitation within 30 days, higher than 64% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update ASP.NET Core 10.0 to 10.0.13 or a later version.
- Update ASP.NET Core 11.0 to 11.0.0-rc.2 or a later version.
- Update ASP.NET Core 8.0 to 8.0.32 or a later version.
- Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | ASP.NET Core 10.0 | 10.0 up to, but not including, 10.0.13 | 10.0.13 |
| Microsoft | ASP.NET Core 11.0 | 11.0 up to, but not including, 11.0.0-rc.2 | 11.0.0-rc.2 |
| Microsoft | ASP.NET Core 8.0 | 8.0 up to, but not including, 8.0.32 | 8.0.32 |
| Microsoft | ASP.NET Core 9.0 | 9.0 up to, but not including, 9.0.21 | 9.0.21 |
| Microsoft | Microsoft Visual Studio 2022 version 17.14 | 17.14.0 up to, but not including, 17.14.42 | 17.14.42 |
| Microsoft | Microsoft Visual Studio 2026 version 18.10 | 18.10.0 up to, but not including, 18.10.4 | 18.10.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (microsoft.com).
Official description
Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an unauthorized attacker to bypass a security feature over a network.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Inconsistent Interpretation of HTTP Requests
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
How developers prevent this class of flaw
- Use a web server that employs a strict HTTP parsing procedure, such as Apache.
- Terminate the client session after each request.
More Inconsistent Interpretation of HTTP Requests vulnerabilities (CWE-444)
Timeline
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in ASP.NET Core 10.0
- 9.4 Critical severity
- 7.5 High severity
Recent Inconsistent Interpretation of HTTP Requests vulnerabilities
- 7.7 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 10.0 Critical severity
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