GestSup before 3.2.61 Remote Code Execution via IMAP Attachment

Advisories

GestSup before 3.2.61 Remote Code Execution via IMAP Attachment

severity: critical
date: 9/25/2026
Affecting: GestSup >= 0, < 3.2.61
CVE: CVE-2026-100389
CWE: CWE-434 Unrestricted Upload of File with Dangerous Type
CVSS: 9.2
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References: https://gestsup.fr/index.php?page=changelog
https://gestsup.fr/index.php?page=download
Credit: SpiizN
Description: GestSup versions before 3.2.61 contain a remote code execution vulnerability in the basic IMAP connector's attachment handling that fails to skip blocked file extensions. Unauthenticated attackers can send emails with PHP attachments to monitored mailboxes, which are written to the web-accessible upload/ticket directory and executed when accessed.

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