Hidden customer modification via reused email record
Published Apr 21, 2026 · Updated Apr 21, 2026
Authorization bypass in FreeScout before 1.8.214 allows remote authenticated users to modify a hidden customer's empty profile fields. With limited customer visibility enabled, POST /customers/ajax action=create omits unique-email validation, so Customer::create() reuses a hidden record matching the submitted email and fills its empty fields from the request. Exploitation requires a non-admin account with access to one mailbox, an inaccessible customer in another mailbox, and empty target fields; the consequence is limited to altering those fields.
Summary
What happened
Authorization bypass in FreeScout before 1.8.214 allows remote authenticated users to modify a hidden customer's empty profile fields. With limited customer visibility enabled, POST /customers/ajax action=create omits unique-email validation, so Customer::create() reuses a hidden record matching the submitted email and fills its empty fields from the request. Exploitation requires a non-admin account with access to one mailbox, an inaccessible customer in another mailbox, and empty target fields; the consequence is limited to altering those fields.
The record
- CVE
- CVE-2026-40590
- Published
- Apr 21, 2026
- Updated
- Apr 21, 2026
- Vendor
- FreeScout
- Product
- FreeScout
- Classifications
- CWE-639, T1565.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 21, 2026CVE publishedPublication date reported by the CVE source.
- Apr 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.8.214
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream authenticated customer-record modification reproductionproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo