What’s Vulnerable › Vulnerabilities

CVE-2025-41707: Phoenix Contact: WebSocket Handler Denial of Service

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-10-14 · updated 2026-10-18
• Weakness: CWE-120

Description

The websocket handler is vulnerable to a denial of service condition. An unauthenticated remote attacker can send a crafted websocket message to trigger the issue without affecting the core functionality.

Affected products

• Phoenix Contact QUINT4-UPS/24DC/24DC/10/EIP: from VC:00 before VC:07 — fixed in VC:07
• Phoenix Contact QUINT4-UPS/24DC/24DC/20/EIP: from VC:00 before VC:07 — fixed in VC:07
• Phoenix Contact QUINT4-UPS/24DC/24DC/40/EIP: from VC:00 before VC:07 — fixed in VC:07
• Phoenix Contact QUINT4-UPS/24DC/24DC/5/EIP: from VC:00 before VC:07 — fixed in VC:07

How to fix

Upgrade to a fixed version: Phoenix Contact QUINT4-UPS/24DC/24DC/10/EIP VC:07; Phoenix Contact QUINT4-UPS/24DC/24DC/20/EIP VC:07; Phoenix Contact QUINT4-UPS/24DC/24DC/40/EIP VC:07; Phoenix Contact QUINT4-UPS/24DC/24DC/5/EIP VC:07. Check the vendor advisory for mitigations.

References

• https://certvde.com/de/advisories/VDE-2025-072
• http://seclists.org/fulldisclosure/2025/Oct/12

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