---
title: "CVE-2026-100389: GestSup - Remote Code Execution"
description: "GestSup < 3.2.61 contains a remote code execution caused by improper handling of blocked file extensions in the basic IMAP connector's attachment processing, letting unauthenticated attackers execute PHP attachments via monitored mailboxes."
url: https://panop.io/threat-heartbeat/CVE-2026-100389/
---

# CVE-2026-100389 GestSup - Remote Code Execution

GestSup < 3.2.61 contains a remote code execution caused by improper handling of blocked file extensions in the basic IMAP connector's attachment processing, letting unauthenticated attackers execute PHP attachments via monitored mailboxes.

CVSS base score 8.1 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.58% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-100389)

## Details

Type

Remote Code Execution

Impact

Remote Code Execution

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Published

25 September 2026

Updated

15 October 2026

Weakness

[CWE-434](https://cwe.mitre.org/data/definitions/434.html)

## Vendor fix

Upgrade to version 3.2.61 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-100389](https://nvd.nist.gov/vuln/detail/CVE-2026-100389)
- [https://gestsup.fr/index.php?page=changelog](https://gestsup.fr/index.php?page=changelog)
- [https://gestsup.fr/index.php?page=download](https://gestsup.fr/index.php?page=download)
- [https://www.vulncheck.com/advisories/gestsup-before-3.2.61-remote-code-execution-via-imap-attachment](https://www.vulncheck.com/advisories/gestsup-before-3.2.61-remote-code-execution-via-imap-attachment)
- [https://blog.spiizn.xyz/articles/remote-code-execution-turning-a-ticket-into-a-new-issue/](https://blog.spiizn.xyz/articles/remote-code-execution-turning-a-ticket-into-a-new-issue/)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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