CVE-2026-18165

@fastify/oauth2 is an OAuth 2.0 plugin for Fastify. In versions from 7.2.0 up to but not including 8.3.0, the plugin validates the OAuth state, and with PKCE the code verifier, by comparing the callback query parameter against an unprefixed, predictable cookie, with no server-side binding to the...

CVE-2026-18165

Summary: CVE-2026-18165 affects @fastify/oauth2 in versions 7.2.0 up to, but not including, 8.3.0. The vulnerability arises from validating the OAuth state and PKCE code verifier by comparing the callback query parameter to an unprefixed, predictable cookie, with no server-side binding to the ini...

EUVD-2026-57601

NextAuth.js provides authentication for Next.js. Prior to@auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32, Auth.js stores the OAuth/OIDC anti-CSRF checks state, nonce, and the PKCE verifier in global cookies that are not bound to the provider that created them. On callback, a check value...

CVE-2026-73419

NextAuth.js/NMD vulnerability CVE-2026-73419 affects Auth.js OAuth/OIDC flow cookies. Prior to Auth.js @auth/core 0.41.3 and NextAuth.js 4.24.15 or 5.0.0-beta.32, state, nonce, and PKCE verifier were stored in global cookies not bound to the originating provider. On callback, a value from one pro...

SUSE CVE-2026-16615

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer...

DEBIAN-CVE-2026-16615

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer...

PKCE Bypass

@cloudflare/workers-oauth-provider is vulnerable to PKCE bypass. The vulnerability is due to missing enforcement of PKCE verification caused by a flaw in the OAuth implementation that lets attackers skip the code challenge check, allowing an attacker to intercept and redeem authorization codes fo...

@cloudflare/workers-oauth-provider PKCE bypass via downgrade attack

Summary 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. Impact PKCE is a defense-in-depth mechanism against certain kinds of attacks and was an optional extension ...

GHSA-QGP8-V765-QXX9 @cloudflare/workers-oauth-provider PKCE bypass via downgrade attack

Summary 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. Impact PKCE is a defense-in-depth mechanism against certain kinds of attacks and was an optional extension ...

GHSA-VH4H-FVQF-Q9WV 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...

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...

CVE-2025-4144 PKCE bypass via downgrade attack

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...

CVE-2025-4144 PKCE bypass via downgrade attack

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...

PT-2025-18345 · Unknown · Workers-Oauth-Provider

Name of the Vulnerable Software and Affected Versions: workers-oauth-provider affected versions not specified Description: The issue is related to the OAuth implementation in workers-oauth-provider, part of the MCP framework. An attacker could cause the PKCE check to be skipped, completely...