Summary
Impact: Information Disclosure. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
What type of information could be disclosed by this vulnerability?
The type of information that could be disclosed if an attacker successfully exploited this vulnerability by bypassing a security feature that is built in to prevent cookies from being read is cookies data and cached sessions. By reading a session cookie, an attacker would be able to sign into the victim’s accounts on a different computer.
Security updates
8.0.34 — https://support.microsoft.com/help/5135243
9.0.23 — https://support.microsoft.com/help/5135242
10.0.15 — https://support.microsoft.com/help/5135241
11.0.0 — https://github.com/dotnet/core/blob/main/release-notes/11.0/11.0.0/11.0.0.md
17.14.45 — https://learn.microsoft.com/en-us/visualstudio/releases/2022/release-notes
18.11.4 — https://learn.microsoft.com/en-us/visualstudio/releases/2026/release-notes
Vulnerabilities 1
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Medium 6.1
ASP.NET Core Information Disclosure Vulnerability
Improper encoding or escaping of output in ASP.NET Core allows an unauthorized attacker to disclose information over a network.
Revision history
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#2
Changes made to the security updates links and information. This is an informational change only.
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#1
Information published.
References
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CVE-2026-109476 ASP.NET Core Information Disclosure Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-109476
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss