Quick answers
- Is CVE-2026-100389 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-100389 being exploited in the wild.
- How severe is CVE-2026-100389?
- High severity, with a CVSS score of 8.1, published 25 September 2026.
- Which products and versions are affected?
- GestSup before 3.2.61.
- Is there a fix for CVE-2026-100389?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-100389 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-100389?
- Check whether you run GestSup at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The IMAP connector in the core/mail.php component fails to enforce blocked file extension rules during attachment handling, allowing PHP files to pass through validation. Attachments are written directly to the web-accessible upload/ticket directory without proper sanitization. An unauthenticated attacker on the network can exploit this by sending a specially crafted email to a monitored mailbox, resulting in arbitrary code execution in the context of the web server.
Affected products
- GestSup GestSup before 3.2.61
Timeline
- 2026-09-25: disclosed