CVE-2026-41228: Froxlor has Local File Inclusion via path traversal in API `def_language` parameter that leads to Remote Code Execution

Severity: critical (CVSS 9.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-23 · updated 2026-06-17
Weakness: CWE-98

Description

Froxlor is open source server administration software. Prior to version 2.3.6, the Froxlor API endpoint `Customers.update` (and `Admins.update`) does not validate the `def_language` parameter against the list of available language files. An authenticated customer can set `def_language` to a path traversal payload (e.g., `../../../../../var/customers/webs/customer1/evil`), which is stored in the database. On subsequent requests, `Language::loadLanguage()` constructs a file path using this value and executes it via `require`, achieving arbitrary PHP code execution as the web server user. 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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