Cross-Origin Redirect Vulnerability in Microsoft Kiota API Client Library
CVE-2026-49336

5.5MEDIUM

Key Information:

Vendor

Microsoft
Status
Kiota-typescript
Vendor
CVE Published:
19 June 2026

What is CVE-2026-49336?

A flaw in the @microsoft/kiota-http-fetchlibrary allows sensitive headers including Authorization and Cookie to be sent to untrusted redirect targets during cross-origin 30x redirects. This vulnerability arises due to a case-sensitive deletion approach in the RedirectHandler, which fails to remove headers effectively due to case mismatches after lower-casing, thereby exposing authentication tokens to potential attackers. This affects all kiota-generated TypeScript SDKs using certain authentication providers like BaseBearerTokenAuthenticationProvider without required custom configurations, necessitating immediate updates to version 1.0.0-preview.102.

Affected Version(s)

kiota-typescript >= 1.0.0-preview.97, < 1.0.0-preview.102

References

https://github.com/microsoft/kiota-typescript/security/ad...
x_refsource_CONFIRM
https://github.com/microsoft/kiota-typescript/commit/09f8...
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CVSS V4

Score:
5.5
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.