CVE-2026-100389: GestSup before 3.2.62 Remote Code Execution via IMAP Attachment

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-25 · updated 2026-09-30
Weakness: CWE-434

Description

GestSup versions before 3.2.62 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.

Affected products

GestSup: before 3.2.62 — fixed in 3.2.62

How to fix

Upgrade to a fixed version: GestSup 3.2.62. Check the vendor advisory for mitigations.

References

https://blog.spiizn.xyz/articles/remote-code-execution-turning-a-ticket-into-a-new-issue/
https://gestsup.fr/index.php?page=changelog
https://gestsup.fr/index.php?page=download
https://www.vulncheck.com/advisories/gestsup-before-3.2.61-remote-code-execution-via-imap-attachment

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