CVE-2025-4143: @cloudflare/workers-oauth-provider missing validation of redirect_uri on authorize endpoint

May 1, 2025

PKCE was implemented in the OAuth implementation in workers-oauth-provider that is part of MCP framework. However, it was found that an attacker could cause the check to be skipped.

References

github.com/advisories/GHSA-4pc9-x2fx-p7vj
github.com/cloudflare/workers-oauth-provider
github.com/cloudflare/workers-oauth-provider/pull/26
github.com/cloudflare/workers-oauth-provider/security/advisories/GHSA-4pc9-x2fx-p7vj
nvd.nist.gov/vuln/detail/CVE-2025-4143

Code Behaviors & Features

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