CVE-2026-41232: Froxlor has an Email Sender Alias Domain Ownership Bypass via Wrong Array Index that Allows Cross-Customer Email Spoofing

Severity: medium (CVSS 5.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-23 · updated 2026-06-17
Weakness: CWE-863

Description

Froxlor is open source server administration software. Prior to version 2.3.6, in `EmailSender::add()`, the domain ownership validation for full email sender aliases uses the wrong array index when splitting the email address, passing the local part instead of the domain to `validateLocalDomainOwnership()`. This causes the ownership check to always pass for non-existent "domains," allowing any authenticated customer to add sender aliases for email addresses on domains belonging to other customers. Postfix's `sender_login_maps` then authorizes the attacker to send emails as those addresses. Version 2.3.6 fixes the issue.

Affected products

froxlor: before 2.3.6 — fixed in 2.3.6

How to fix

Upgrade to a fixed version: froxlor 2.3.6. Check the vendor advisory for mitigations.

References

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