Critical severity · published Oct 13, 2026
CVE-2026-70188
ASP.NET Core Security Feature Bypass Vulnerability
9.1
CVSS
0.9%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 61% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AC
ASP.NET Core 10.0 · Microsoft
10.0 before 10.0.13 · source: vendor
AC
ASP.NET Core 11.0 · Microsoft
11.0 before 11.0.0-rc.2 · source: vendor
AC
ASP.NET Core 8.0 · Microsoft
8.0 before 8.0.32 · source: vendor
AC
ASP.NET Core 9.0 · Microsoft
9.0 before 9.0.21 · source: vendor
MV
Microsoft Visual Studio 2022 version 17.14 · Microsoft
17.14.0 before 17.14.42 · source: vendor
MV
Microsoft Visual Studio 2026 version 18.10 · Microsoft
18.10.0 before 18.10.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-70188
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-70188
vendor-advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70188
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