Microsoft Identity Web Exposes Client Secrets and Certificate Information in Service Logs
Impact
What kind of vulnerability is it? Who is impacted?
Description: This vulnerability affects confidential client applications, including daemons, web apps, and web APIs. Under specific circumstances, sensitive information such as client secrets or certificate details may be exposed in the service logs of these applications. Service logs are intended to be handled securely.
Impact: The vulnerability impacts service logs that meet the following criteria:
- Logging Level: Logs are generated at the information level.
- Credential Descriptions: containing:
- Local file paths with passwords.
- Base64 encoded values.
- Client secret.
Additionally, logs of services using Base64 encoded certificates or certificate paths with password credential descriptions are also affected if the certificates are invalid or expired, regardless of the log level. Note that these credentials are not usable due to their invalid or expired status.
If your service logs are handled securely, you are not impacted.
Otherwise, the following table shows when you can be impacted
| Log Level Information for Microsoft.Identity.Web | Invalid Certificate | |
|---|---|---|
| One of the ClientCredentials credential description has a CredentialSource = Base64Encoded or (CredentialSource = Path) | Impacted | Impacted |
| One of the ClientCredentials credential description is a Client secret (CredentialSource = ClientSecret) | Impacted | Not impacted |
| Other credential descriptions | Not Impacted | Not Impacted |
Patches
Has the problem been patched? What versions should users upgrade to? To mitigate this vulnerability, update to Microsoft.Identity.Web 3.8.2 or Microsoft.Identity.Abstractions 9.0.0.
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading? You can work around the issue in the following ways:
-
Ensure that service logs are handled securely and access to logs is restricted
-
Don’t use
LogLevel = Informationfor the Microsoft.Identity.Web namespace
Recommendation for production environment
Avoid using ClientCredentials with CredentialDescriptions which CredentialSource is ClientSecret, or Base64Encoded, or Path. Rather use certificate from KeyVault or a certificate store, or Federation identity credential with Managed identity.
References
Are there any links users can visit to find out more?
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| .NET (NuGet) | Microsoft.Identity.Abstractions | >= 7.1.0, < 9.0.0 | 9.0.0 |
| .NET (NuGet) | Microsoft.Identity.Web | >= 3.2.0, < 3.8.2 | 3.8.2 |
References
- CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N- Weakness (CWE)
CWE-532- Platform
- .NET (NuGet)
- Package
Microsoft.Identity.Abstractions, Microsoft.Identity.Web- Disclosed
- 09.04.2025
- Updated
- 11.10.2026 11:23
Sources and licenses
OSV / GitHub Advisory Database - GHSA-rpq8-q44m-2rpg - CC BY 4.0
Vulnerability history: Microsoft.Identity.Web
All published vulnerabilities of this package (.NET (NuGet)), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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