CRITICAL: CVE-2026-53595 (CVSS 9.4) — multiple products

CVE: CVE-2026-53595

CVSS: 9.4 (3.1) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

Severity: CRITICAL

Status: Critical advisory

Affected

_See vendor advisory_

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.

Verified Sources

• NVD entry
• GitHub Advisory
• MITRE

References

• https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-jqj5-r72v-v29g

_Validated by the Lyrie Threat Intelligence Pipeline — 3 independent sources confirmed before publication. No speculation._