CVE-2023-5771: HTML injection in AdminUI through email subject

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-11-06 · updated 2026-06-17
Weakness: CWE-79

Description

Proofpoint Enterprise Protection contains a stored XSS vulnerability in the AdminUI. An unauthenticated attacker can send a specially crafted email with HTML in the subject which triggers XSS when viewing quarantined messages. This issue affects Proofpoint Enterprise Protection: from 8.20.0 before patch 4796, from 8.18.6 before patch 4795 and all other prior versions.

Affected products

Proofpoint Enterprise Protection: before 8.18.6; 8.18.6, 8.20.0 — fixed in 8.18.6

How to fix

Upgrade to a fixed version: Proofpoint Enterprise Protection 8.18.6. Check the vendor advisory for mitigations.

References

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