Thelia: CVE-2026-103535

Thelia v2.6.1 contains path traversal and PHP code injection vulnerabilities in its translation editor that can be chained to achieve remote code execution. The item_name parameter, used to build the translation file's write path, does not sanitize directory traversal sequences such as ../. This enables an authenticated user with UPDATE-level permissions on admin.configuration.language to write files outside the expected templates/ directory, including to web‑accessible paths. Separately, the translation‑writing logic does not escape \ in user‑supplied values, allowing inputs to break out of the PHP string literal and inject executable code into the translation file. Chained together, these flaws allow a malicious PHP file to be written to a web-accessible path and executed with the web‑server’s privileges.