CVE-2023-36521

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-07-11 · updated 2026-10-23
Weakness: CWE-770

Description

A vulnerability has been identified in SIMATIC MV540 H (All versions < V3.3.4), SIMATIC MV540 S (All versions < V3.3.4), SIMATIC MV550 H (All versions < V3.3.4), SIMATIC MV550 S (All versions < V3.3.4), SIMATIC MV560 U (All versions < V3.3.4), SIMATIC MV560 X (All versions < V3.3.4). The result synchronization server of the affected products contains a vulnerability that may lead to a denial of service condition. An attacker may cause a denial of service situation of all socket-based communication of the affected products if the result server is enabled.

Affected products

Siemens Simatic Mv540 H Firmware: before 3.3.4 — fixed in 3.3.4
Siemens Simatic Mv540 S Firmware: before 3.3.4 — fixed in 3.3.4
Siemens Simatic Mv550 H Firmware: before 3.3.4 — fixed in 3.3.4
Siemens Simatic Mv550 S Firmware: before 3.3.4 — fixed in 3.3.4
Siemens Simatic Mv560 U Firmware: before 3.3.4 — fixed in 3.3.4
Siemens Simatic Mv560 X Firmware: before 3.3.4 — fixed in 3.3.4

How to fix

Upgrade to a fixed version: Siemens Simatic Mv540 H Firmware 3.3.4; Siemens Simatic Mv540 S Firmware 3.3.4; Siemens Simatic Mv550 H Firmware 3.3.4; Siemens Simatic Mv550 S Firmware 3.3.4; Siemens Simatic Mv560 U Firmware 3.3.4; Siemens Simatic Mv560 X Firmware 3.3.4. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2023-36521 or the next vulnerability affects your stack