Duplicate Advisory: @cloudflare/workers-oauth-provider PKCE bypass via downgrade attack
Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-qgp8-v765-qxx9. This link is maintained to preserve external references. Original Description PKCE was implemented in the OAuth implementation in workers-oauth-provider that is part of MCP framework https://github.com/cloudflare/workers-mcp . However, it was found that an attacker could cause the check to be skipped. Fixed in: https://github.com/cloudflare/workers-oauth-provider/pull/27 https://github.com/cloudflare/workers-oauth-provider/pull/27 Impact: PKCE is a defense-in-depth mechanism against certain kinds of attacks …