Microsoft Identity Web Exposes Client Secrets and Certificate Information in Service Logs

published 2025-04-09 19 mo ago modified 2026-06-17 4 mo ago also GHSA-rpq8-q44m-2rpg , EUVD-2025-10551

cvss: 4.7; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 0%
public exploits: 0; none known

Microsoft Identity Web is a library which contains a set of reusable classes used in conjunction with ASP.NET Core for integrating with the Microsoft identity platform (formerly Azure AD v2.0 endpoint) and AAD B2C. 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. Service logs generated at the information level or credential descriptions containing local file paths with passwords, Base64 encoded values, or 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. To mitigate this vulnerability, update to Microsoft.Identity.Web 3.8.2 or Microsoft.Identity.Abstractions 9.0.0.

Patch / fix

fixed in 2

nuget Microsoft.Identity.Web 3.8.2
nuget Microsoft.Identity.Abstractions 9.0.0

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 19 mo ago (2025-04-09)

Exploit prediction

0.10% chance of exploitation in the next 30 days, higher than 0% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.7	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
GitHub	3.1	4.7	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
nuget	Microsoft.Identity.Web	>=3.2.0, <3.8.2	3.8.2
nuget	Microsoft.Identity.Abstractions	>=7.1.0, <9.0.0	9.0.0

Affected products

AzureAD microsoft-identity-web

Classification

Weakness

CWE-532 Insertion of Sensitive Information into Log File

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary