hoppscotch is an open source API development ecosystem. Prior to version 2026.2.0, an unauthenticated attacker can overwrite the entire infrastructure configuration of a self-hosted Hoppscotch instance including OAuth provider credentials and SMTP settings by sending a single HTTP POST request with no authentication. The endpoint POST /v1/onboarding/config has no authentication guard and performs no check on whether onboarding was already completed. A successful exploit allows the attacker to replace the instance's Google/GitHub/Microsoft OAuth application credentials with their own, causing all subsequent user logins via SSO to authenticate against the attacker's OAuth app. The attacker captures OAuth tokens and email addresses of every user who logs in after the exploit. Additionally, the endpoint returns a recovery token that can be used to read all stored secrets in plaintext, including SMTP passwords and any other configured credentials. Version 2026.2.0 fixes the issue.
The POST endpoint /v1/onboarding/config lacks any authentication controls or verification of whether the onboarding process was previously completed. An attacker sends a single HTTP POST request, replacing the OAuth configuration (Google, GitHub, Microsoft) with their own application data, causing all subsequent SSO logins to authenticate against the OAuth application controlled by the attacker. Additionally, the endpoint returns a recovery token that enables reading all stored secrets in plain text, including SMTP passwords and other configured credentials.
An attacker can intercept OAuth tokens and email addresses of all users logging in after the attack, as well as gain access to all instance-stored secrets in plain text, leading to complete takeover of the environment.
Hoppscotch should be updated to version 2026.2.0, which fixes the described vulnerability. Details are available in the vendor references: https://github.com/hoppscotch/hoppscotch/releases/tag/2026.2.0
Hoppscotch (self-hosted) in all versions prior to 2026.2.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NHoppscotch
APPHoppscotch< 2026.2.0
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