Auth bypass in Siemens Sinamics Sl150

CVE-2021-31337

The Telnet service of the SIMATIC HMI Comfort Panels system component in affected products does not require authentication, which may allow a remote attacker to gain access to the device if the service is enabled. Telnet is disabled by default on the SINAMICS Medium Voltage Products (SINAMICS SL150: All versions, SINAMICS SM150: All versions, SINAMICS SM150i: All versions).

Vulnerability class: Broken Authentication

EPSS: 0.017 (74.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-31337?
CVE-2021-31337 is a critical-severity vulnerability in Siemens Sinamics Sl150, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2021-06-28.
How severe is CVE-2021-31337?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-31337 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.