CVE-2026-53595 FreeScout vulnerable to anonymous account takeover via /user-setup empty invite_hash on MySQL
An anonymous attacker can take over the lowest-ID activated user account in FreeScout by exploiting MySQL string comparison flaws in the user setup endpoint.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-53595?
CVE-2026-53595 is a critical authentication bypass vulnerability in freescout-help-desk freescout, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.224, the public endpoint `POST /user-setup/{hash}/{invite_sent_at}` (`OpenController@userSetupSave`) selects the target account solely by its `invite_hash` column, then overwrites that account's email and password and logs in as it. No authentication, cookie, or prior session is required. After a user activates, FreeScout sets `invite_hash` to the empty string. On MySQL and MariaDB, `VARCHAR` equality ignores trailing spaces, so a single URL-encoded space (`%20`) matches the stored empty string and selects the lowest-id activated user. The expiry guard decrypts `invite_sent_at` with the target's password hash, but `Helper::decrypt` returns its raw input unchanged when decryption fails. A plaintext numeric value such as `9999999999` therefore passes the time-to-live check without any secret. The result is that an anonymous attacker sets the email and password of the lowest-id activated FreeScout account (a support agent, or an administrator if one was added by invitation) and authenticates as that account. Version 1.8.224 contains a fix.
Which versions are affected by CVE-2026-53595?
How do I fix CVE-2026-53595?
No fix has been published for CVE-2026-53595 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-53595 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53595 exists.
Public exploit code: 1 Nuclei template and 1 proofs of concept on GitHub.
Sources
Also known as GHSA-jqj5-r72v-v29g.