CVE-2021-25659

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-08-10 · updated 2026-06-17
Weakness: CWE-400

Description

A vulnerability has been identified in Automation License Manager 5 (All versions), Automation License Manager 6 (All versions < V6.0 SP9 Update 2). Sending specially crafted packets to port 4410/tcp of an affected system could lead to extensive memory being consumed and as such could cause a denial-of-service preventing legitimate users from using the system.

Affected products

Siemens AG Automation License Manager 5: from 5.0.0 before 6.0.9 — fixed in 6.0.9

How to fix

Upgrade to a fixed version: Siemens AG Automation License Manager 5 6.0.9. Check the vendor advisory for mitigations.

References

https://cert-portal.siemens.com/productcert/pdf/ssa-158827.pdf
https://cert-portal.siemens.com/productcert/pdf/ssa-158827.pdf

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