Vulnerability · CVE-2026-70188
Microsoft Security Advisory CVE-2026-70188 - ASP.NET Core Security Feature Bypass Vulnerability
Published Oct 13, 2026 · Microsoft Security Advisory -
Check if you run it
No confirmed exploitation is on record for CVE-2026-70188. EPSS is 0.83%. Act only if a listed version of Microsoft Security Advisory - is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (Microsoft Security Advisory -).
- No version range is stored. A customer cannot check an installed version against this record.
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Unknown—
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.83%
- Remediation
- Not established
- Affected products
- nuget microsoft.aspnetcore.app.runtime.linux-arm64 · nuget microsoft.aspnetcore.app.runtime.linux-musl-arm64 · nuget microsoft.aspnetcore.app.runtime.osx-arm64 · nuget microsoft.aspnetcore.app.runtime.win-x86
Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Server.Kestrel.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. Kestrel accepts newline characters in HTTP/2 request trailers and values retrieved from the dynamic HPACK table instead of treating them as malformed.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- nuget microsoft.aspnetcore.app.runtime.linux-arm64version unspecified
- nuget microsoft.aspnetcore.app.runtime.linux-musl-arm64version unspecified
- nuget microsoft.aspnetcore.app.runtime.osx-arm64version unspecified
- nuget microsoft.aspnetcore.app.runtime.win-x86version unspecified
How to fix CVE-2026-70188
Recommended remediation
No required-action text, fix commit, or clear fixed-version range is stored yet.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-70188. EPSS is 0.83%. Act only if a listed version of Microsoft Security Advisory - is installed.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
No weakness class is stored. EPSS 0.83%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Oct 13, 2026 · GitLab Advisory Database
Detected
Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Server.Kestrel.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. Kestrel accepts newline characters in HTTP/2 request trailers and values retrieved from the dynamic HPACK table instead of treating them as ma
Sources
- CVE.orgVulnerability recordCVE-2026-70188
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-70188
30-day exploitation probability 0.8%
first.org - GitLab Advisory DatabasePackage advisoryCVE-2026-70188
Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Server.Kestrel.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. Kestrel accepts newline characters in HTTP/2 request trailers and values retrieved from the dynamic HPACK table instead of treating them as ma
advisories.gitlab.com
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.