CVE-2026-100389

GestSup before 3.2.62 Remote Code Execution via IMAP Attachment

Published Sep 25, 2026 CVSS 4.0 · 9.2 Critical EPSS < 1% KEV · Not listed
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.

Analysis

AI-generated

Technical impact

GestSup versions prior to 3.2.62 expose unauthenticated attackers to remote code execution via the IMAP attachment handling. The flaw arises because the basic IMAP connector fails to reject attachments with blocked file extensions. When attackers submit emails containing PHP files to monitored mailboxes, the attachments are written to the web‑accessible upload/ticket directory and can be executed when accessed. This vulnerability maps to CWE‑434 and can compromise confidentiality, integrity, and availability on affected systems.

Affected Systems

The affected product is GestSup earlier than version 3.2.62; all deployments of GestSup running a version before 3.2.62 are vulnerable. The vendor identifier is GestSup, with the product named GestSup. No specific sub‑version range is defined beyond the advisory notice of the 3.2.62 release.

Risk and Exploitability

The CVSS score of 9.2 labels this flaw as critical, and the lack of authentication requirements combined with the ability to write executable files directly to a web‑root folder make exploitation practical. The updated EPSS score remains less than 1%, indicating a low but nonzero probability of exploitation. The vulnerability is not listed in the CISA KEV catalog, but the remote code execution capability permits an attacker to execute arbitrary code on the server once a PHP payload has been delivered and accessed. Because any mailbox monitored by the compromised GestSup instance can be targeted, the threat is broad and immediate compromise of the underlying host is possible.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Upgrade GestSup to version 3.2.62 or later to apply the vendor‑provided fix.
  • If an upgrade is not feasible, disable the IMAP attachment feature or restrict it to authenticated users only.
  • Reconfigure the upload/ticket directory so that it is not publicly accessible or remove execution permissions for uploaded files, and enforce file‑type validation to block PHP or other executable extensions.

Generated by OpenCVE AI on September 30, 2026 at 13:07 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
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. 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.
Title GestSup before 3.2.61 Remote Code Execution via IMAP Attachment GestSup before 3.2.62 Remote Code Execution via IMAP Attachment
References
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title GestSup before 3.2.61 Remote Code Execution via IMAP Attachment
First Time appeared Gestsup
Gestsup gestsup
Weaknesses CWE-434
CPEs cpe:2.3:a:gestsup:gestsup:*:*:*:*:*:*:*:*
Vendors & Products Gestsup
Gestsup gestsup
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.2, 'vector': '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'}

Weaknesses
  • CWE-434

    Unrestricted Upload of File with Dangerous Type

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Sep 30, 2026, 11:15 AM
Reserved
Sep 25, 2026, 7:47 PM
Status
Deferred
Published
Sep 25, 2026, 9:17 PM
Modified
Sep 30, 2026, 5:32 PM