CVE-2025-59934
Prior to version 4.0.1, Formbricks is missing JWT signature verification.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (9.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 9.4 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
- EPSS
- 9.14% probability · 95th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-287, CWE-345, CWE-347
- Source
- security-advisories@github.com
EPSS 9.1% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/formbricks/formbricks/blob/843110b0d6c37b5c0da54291616f84c91c55c4fc/apps/web/lib/jwt.ts#L114-L117
- https://github.com/formbricks/formbricks/commit/eb1349f205189d5b2d4a95ec42245ca98cf68c82
- https://github.com/formbricks/formbricks/pull/6596
- https://github.com/formbricks/formbricks/security/advisories/GHSA-7229-q9pv-j6p4
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.