What’s Vulnerable › Vulnerabilities

CVE-2026-102374: GestSup before 3.2.62 Stored XSS via Double-Decoded Email Subject in OAuth IMAP Connector

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-29 · updated 2026-09-30
• Weakness: CWE-79

Description

GestSup versions before 3.2.62 contain a stored cross-site scripting vulnerability in the IMAP OAuth connector that double-decodes MIME-encoded email subjects after HTML escaping. Unauthenticated attackers can send crafted emails to monitored mailboxes with nested MIME encoded-words to inject JavaScript that executes in technician sessions when viewing tickets.

Affected products

• GestSup: before 3.2.62 — fixed in 3.2.62

How to fix

Upgrade to a fixed version: GestSup 3.2.62. Check the vendor advisory for mitigations.

References

• https://blog.spiizn.xyz/articles/remote-code-execution-turning-a-ticket-into-a-new-issue/
• https://gestsup.fr/index.php?page=changelog
• https://gestsup.fr/index.php?page=download
• https://gestsup.fr/index.php?page=download&channel=stable&version=3.2.62&type=patch
• https://www.vulncheck.com/advisories/gestsup-before-3.2.62-stored-xss-via-double-decoded-email-subject-in-oauth-imap-connector

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