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Vulnerability record · CVE-2026-100389 · published 25 September 2026

CVE-2026-100389: Unrestricted file upload vulnerability

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.

9.2 CVSS 4.0 Critical EPSS 0.57% · top 54.8% CWE-434 · Unrestricted file upload Received
9.2CVSS 4.0 base score
0.57%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
3References
25 Sep 2026Last modified by NVD

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.

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

LinkTags
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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Source: NIST National Vulnerability Database (record CVE-2026-100389), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.