CVE-2021-33903

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-10-07 · updated 2026-06-17

Description

In LCOS 10.40 to 10.42.0473-RU3 with SNMPv3 enabled on LANCOM devices, changing the password of the root user via the CLI does not change the password of the root user for SNMPv3 access. (However, changing the password of the root user via LANconfig does change the password of the root user for SNMPv3 access.)

Affected products

Lancom-Systems Lcos: from 10.40 before 10.42.0473; 10.42.0473, 10.42.0473-release_update1, 10.42.0473-release_update2, 10.42.0473-release_update3 — fixed in 10.42.0473

How to fix

Upgrade to a fixed version: Lancom-Systems Lcos 10.42.0473. Check the vendor advisory for mitigations.

References

https://www.nmedv.de/wp-content/uploads/2021/10/NME-2021-001.txt
https://www.nmedv.de/wp-content/uploads/2021/10/NME-2021-001.txt

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