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Fencer Vulns
high 7.5

CVE-2021-25659 json

A vulnerability has been identified in Automation License Manager 5 (All versions), Automation License Manager 6 (All versions < V6.0 SP9 U…

published 2021-08-10 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-12551

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 64%
public exploits
0
none known

Summary

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.

Patch / fix

  • siemens automation_license_manager 6.0.9

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-222-02 updated cvss 5.9

Siemens Automation License Manager

  • Siemens Automation License Manager 5
    affected: mitigation, no fix available
  • Siemens Automation License Manager 6 <V6.0_SP9_Update_2
    affected: fixed in V6.0, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

1.04% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • Siemens Automation License Manager 5
  • Siemens Automation License Manager 6

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.