CVE-2023-5770: Proofpoint Enterprise Protection

Medium severity, CVSS 5.4. EPSS: 0.3% chance of exploitation in the next 30 days.

Proofpoint Enterprise Protection contains a vulnerability in the email delivery agent that allows an unauthenticated attacker to inject improperly encoded HTML into the email body of a message through the email subject. The vulnerability is caused by inappropriate encoding when rewriting the email before delivery.This issue affects Proofpoint Enterprise Protection: from 8.20.2 before patch 4809, from 8.20.0 before patch 4805, from 8.18.6 before patch 4804 and all other prior versions.

Affected products

• Proofpoint Enterprise Protection: version 8.18.6 only; version 8.20.0 only; version 8.20.2 only

Published 2024-01-09. Last modified 2026-06-17.