SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-100389

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.

CRITICAL 9.2EPSS 0.58%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.58%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0
9.2 CRITICALCVSS: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/M
EPSS
0.58% probability · 47th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-434
Source
disclosure@vulncheck.com
EPSS trend
0%3%5%26 September 2026: 0.57%26 October 2026: 0.58%26 September 202626 October 2026

EPSS moved from 0.6% on 26 September 2026 to 0.6% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.