Vulnerability · Published Sep 26, 2025 · Assigned by GitHub_M
CVE-2025-59934Formbricks missing JWT signature verification
Critical 9.4
In plain English
A critical-severity insufficient verification of data authenticity in formbricks from formbricks. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 9.1% (higher than 95% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
Formbricks is an open source qualtrics alternative. Prior to version 4.0.1, Formbricks is missing JWT signature verification. This vulnerability stems from a token validation routine that only decodes JWTs (jwt.decode) without verifying their signatures. Both the email verification token login path and the password reset server action use the same validator, which does not check the token’s signature, expiration, issuer, or audience. If an attacker learns the victim’s actual user.id, they can craft an arbitrary JWT with an alg: "none" header and use it to authenticate and reset the victim’s password. This issue has been patched in version 4.0.1.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| formbricks | formbricks | < 4.0.1 |
Weakness: CWE-347, CWE-345, CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
References
- https://github.com/formbricks/formbricks/security/advisories/GHSA-7229-q9pv-j6p4 x_refsource_CONFIRM
- https://github.com/formbricks/formbricks/pull/6596 x_refsource_MISC
- https://github.com/formbricks/formbricks/commit/eb1349f205189d5b2d4a95ec42245ca98cf68c82 x_refsource_MISC
- https://github.com/formbricks/formbricks/blob/843110b0d6c37b5c0da54291616f84c91c55c4fc/apps/web/lib/jwt.ts#L114-L117 x_refsource_MISC