{"id":"CVE-2026-49336","summary":"@microsoft/kiota-http-fetchlibrary: Bearer token and Cookie leak across origin on redirect due to case-mismatched scrub in fetchRequestAdapter","details":"@microsoft/kiota-http-fetchlibrary provides TypeScript libraries for Kiota-generated API clients. In versions 1.0.0-preview.97 through 1.0.0-preview.101, `@microsoft/kiota-http-fetchlibrary`'s `RedirectHandler` is documented as stripping `Authorization` and `Cookie` from cross-origin redirect targets, but the default `scrubSensitiveHeaders` callback in `RedirectHandlerOptions` uses case-sensitive property deletion (`delete headers.Authorization`, `delete headers.Cookie`) on a headers object that `FetchRequestAdapter.getRequestFromRequestInformation` has already lower-cased. The delete therefore targets keys that do not exist, the scrub is a no-op, and any Bearer token or Cookie attached by a kiota-generated SDK is forwarded to an attacker-controlled host across a 30x redirect. This is reachable in the default middleware chain (`MiddlewareFactory.getDefaultMiddlewares`) with no custom configuration, and applies to every kiota-generated TypeScript SDK that uses `BaseBearerTokenAuthenticationProvider` or any other authentication provider that sets the `Authorization` request header. Version 1.0.0-preview.102 patches the issue.","aliases":["GHSA-396q-4vc8-28x9"],"modified":"2026-07-09T18:51:43.372447818Z","published":"2026-06-19T18:19:03.222Z","related":["CGA-crxv-m6qw-55r4"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-178","CWE-200"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49336.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49336.json"},{"type":"ADVISORY","url":"https://github.com/microsoft/kiota-typescript/security/advisories/GHSA-396q-4vc8-28x9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49336"},{"type":"FIX","url":"https://github.com/microsoft/kiota-typescript/commit/09f8bd9b34d68bf412a9b78f6ca7e7961ef14974"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/microsoft/kiota-typescript","events":[{"introduced":"9f0ab765293ae34191c1f5966dba20454e12a255"},{"fixed":"8c1bb2a11fb1b6873d35129308580ce6da877a71"}],"database_specific":{"extracted_events":[{"introduced":"1.0.0-preview.97"},{"fixed":"1.0.0-preview.102"}],"source":"AFFECTED_FIELD"}}],"versions":["@microsoft/kiota-serialization-text@1.0.0-preview.101","@microsoft/kiota-serialization-multipart@1.0.0-preview.101","@microsoft/kiota-serialization-json@1.0.0-preview.101","@microsoft/kiota-serialization-form@1.0.0-preview.101","@microsoft/kiota-http-fetchlibrary@1.0.0-preview.101","@microsoft/kiota-bundle@1.0.0-preview.101","@microsoft/kiota-authentication-spfx@1.0.0-preview.101","@microsoft/kiota-authentication-azure@1.0.0-preview.101","@microsoft/kiota-abstractions@1.0.0-preview.101","@microsoft/kiota-serialization-text@1.0.0-preview.100","@microsoft/kiota-serialization-multipart@1.0.0-preview.100","@microsoft/kiota-serialization-json@1.0.0-preview.100","@microsoft/kiota-serialization-form@1.0.0-preview.100","@microsoft/kiota-http-fetchlibrary@1.0.0-preview.100","@microsoft/kiota-bundle@1.0.0-preview.100","@microsoft/kiota-authentication-spfx@1.0.0-preview.100","@microsoft/kiota-authentication-azure@1.0.0-preview.100","@microsoft/kiota-abstractions@1.0.0-preview.100","@microsoft/kiota-serialization-text@1.0.0-preview.99","@microsoft/kiota-serialization-multipart@1.0.0-preview.99","@microsoft/kiota-serialization-json@1.0.0-preview.99","@microsoft/kiota-serialization-form@1.0.0-preview.99","@microsoft/kiota-http-fetchlibrary@1.0.0-preview.99","@microsoft/kiota-bundle@1.0.0-preview.99","@microsoft/kiota-authentication-spfx@1.0.0-preview.99","@microsoft/kiota-authentication-azure@1.0.0-preview.99","@microsoft/kiota-abstractions@1.0.0-preview.99","@microsoft/kiota-serialization-text@1.0.0-preview.98","@microsoft/kiota-serialization-multipart@1.0.0-preview.98","@microsoft/kiota-serialization-json@1.0.0-preview.98","@microsoft/kiota-serialization-form@1.0.0-preview.98","@microsoft/kiota-http-fetchlibrary@1.0.0-preview.98","@microsoft/kiota-bundle@1.0.0-preview.98","@microsoft/kiota-authentication-spfx@1.0.0-preview.98","@microsoft/kiota-authentication-azure@1.0.0-preview.98","@microsoft/kiota-abstractions@1.0.0-preview.98","@microsoft/kiota-serialization-text@1.0.0-preview.97","@microsoft/kiota-serialization-multipart@1.0.0-preview.97","@microsoft/kiota-serialization-json@1.0.0-preview.97","@microsoft/kiota-serialization-form@1.0.0-preview.97","@microsoft/kiota-http-fetchlibrary@1.0.0-preview.97","@microsoft/kiota-bundle@1.0.0-preview.97","@microsoft/kiota-authentication-spfx@1.0.0-preview.97","@microsoft/kiota-authentication-azure@1.0.0-preview.97","@microsoft/kiota-abstractions@1.0.0-preview.97"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49336.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P"}]}