CVE-2021-27393

moderate-risk

Published 2021-04-22

A vulnerability has been identified in Nucleus NET (All versions), Nucleus ReadyStart V3 (All versions < V2013.08), Nucleus Source Code (Versions including affected DNS modules). The DNS client does not properly randomize UDP port numbers of DNS requests. That could allow an attacker to poison the DNS cache or spoof DNS resolving.

Do I need to act?

0.22% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 5.3/10 Medium

NETWORK / LOW complexity

Affected Products (3)

Nucleus Net

Nucleus Readystart V3

Nucleus Source Code

Affected Vendors

Siemens

References (2)

Vendor Advisory https://cert-portal.siemens.com/productcert/pdf/ssa-201384.pdf

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moderate-risk

Severity 21/34 · High

Exploitability 1/34 · Minimal

Exposure 9/34 · Low