CVE-2026-18165

A flaw was found in @fastify/oauth2, an OAuth 2.0 plugin for Fastify. This vulnerability allows a remote attacker to perform a Login Cross-Site Request Forgery CSRF attack. By planting predictable OAuth state and code verifier cookies, an attacker can trick a victim's browser into completing an...

Cross-site Request Forgery (CSRF)

Overview @fastify/oauth2 is a Perform login using oauth2 protocol Affected versions of this package are vulnerable to Cross-site Request Forgery CSRF due to the OAuth state-check cookies in the index.js authorization flow. An attacker can log a victim into the attacker’s account by planting...

@appweaver/core (>=1.0.0, <=1.4.1), @bryopsida/object-store (>=0.1.0, <=0.1.7) +11 more potentially affected by CVE-2026-18165 via @fastify/oauth2 (>=7.9.0, <=8.2.0)

@fastify/oauth2 NPM version =7.9.0, =1.0.0, =0.1.0, =0.0.1, =0.0.1, =0.0.1, =0.0.1, =0.0.1, =0.13.0, =1.4.30, =1.2.0, =0.0.14, =0.0.19 Source cves: CVE-2026-18165 Source advisory: SNYK:JS-FASTIFYOAUTH2-18902506...

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 @fastify/oauth2 vulnerable to Login CSRF via plantable OAuth state cookies

@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 @fastify/oauth2 vulnerable to Login CSRF via plantable OAuth state cookies

@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 @fastify/oauth2 vulnerable to Login CSRF via plantable OAuth state cookies

@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...

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...

EUVD-2026-59767

@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: Cross-Site Request Forgery (CSRF)

@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...

PT-2026-73032

@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...

GHSA-G8X5-P9QC-CF95 @fastify/oauth2 vulnerable to Cross Site Request Forgery due to reused Oauth2 state

Impact All versions of @fastify/oauth2 used a statically generated state parameter at startup time and were used across all requests for all users. The purpose of the Oauth2 state parameter is to prevent Cross-Site-Request-Forgery attacks. As such, it should be unique per user and should be...

Cross-Site Request Forgery (CSRF)

fastify-oauth2, is vulnerable to Cross-Site Request Forgery. The vulnerability exists due to lack of randomness in the state parameter of index.js which allows an attacker to execute operations within the victim's session, leading to unauthorized access to user accounts...

Duplicate Advisory: @fastify/oauth2 Oauth2 state parameter reuse

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-g8x5-p9qc-cf95. This link is maintained to preserve external references. Original Description All versions of @fastify/oauth2 used a statically generated state parameter at startup time and were used across all...

PT-2023-23563 · Unknown · @Fastify/Oauth2

Name of the Vulnerable Software and Affected Versions: @fastify/oauth2 versions prior to 7.2.0 Description: The issue arises from the statically generated state parameter used across all requests for all users, which should be unique per user to prevent Cross-Site-Request-Forgery attacks. The...

PT-2023-25393 · Unknown · @Fastify/Oauth2

Name of the Vulnerable Software and Affected Versions: @fastify/oauth2 versions prior to 7.2.0 Description: The issue is related to cross-site request forgery CSRF due to the use of a statically generated state parameter across all requests for all users. This parameter should be unique per user...