CVE-2026-53595 json
FreeScout vulnerable to anonymous account takeover via /user-setup empty invite_hash on MySQL
published 2026-07-20 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-46094
- cvss
- 9.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.9%
- EPSS 1.9% chance of exploitation in 30 days, percentile 80%
- public exploits
- 0
- none known, plus a Nuclei check
Summary
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.
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- total
- Assessed
- 3 mo ago
Exploit prediction
1.94% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- Nuclei template FreeScout < 1.8.224 - Invite Hash Authorization Bypass nuclei detection template
- github.com https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-jqj5-r72v-v29g referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L |
Affected products
- freescout-help-desk freescout
Classification
References
Sources
- CVE List CVE-2026-53595
- NVD CVE-2026-53595
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.