Improper Handling of Case Sensitivity Affecting @microsoft/kiota-http-fetchlibrary package, versions >=1.0.0-preview.97 <1.0.0-preview.102
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-MICROSOFTKIOTAHTTPFETCHLIBRARY-17420044
- published23 Jun 2026
- disclosed19 Jun 2026
- credittonghuaroot
Introduced: 19 Jun 2026
NewCVE-2026-49336 (opens in a new tab)How to fix?
Upgrade @microsoft/kiota-http-fetchlibrary to version 1.0.0-preview.102 or higher.
Overview
@microsoft/kiota-http-fetchlibrary is an implementation using the Fetch API to make requests.
Affected versions of this package are vulnerable to Improper Handling of Case Sensitivity via the executeWithRedirect redirect handling in redirectHandlerOptions.ts. An attacker can capture Authorization, Cookie, or Proxy-Authorization credentials by inducing a redirect to a different host or scheme. The vulnerable header scrub deleted only headers.Authorization and headers.Cookie, so lower-cased header names were left on redirected requests and forwarded to the next origin. This exposes bearer tokens, session cookies, and proxy credentials to the redirect target, increasing the risk of account takeover or credential disclosure for clients that follow untrusted redirects.
Notes
- The default redirect scrub runs in the standard middleware chain, so applications that rely on the library’s built-in redirect handling are exposed without extra configuration.