CVE-2026-33389 PUBLISHED

Disabled and non-configurable certificate/host key validation in Smart Polling in Guardian/CMC before 26.3.0 and Arc before v2.7.0

Assigner: Nozomi
Reserved: 19.03.2026 Published: 08.09.2026 Updated: 08.09.2026

An improper certificate/host key validation vulnerability was discovered in the Smart Polling functionality, which established encrypted connections to target devices without validating the remote host's identity, and no option was provided to enable it. A man-in-the-middle attacker positioned between a sensor and a polled device can, during a polling session, impersonate the device and intercept the communication, including the credentials used to access it. The captured credentials can then be replayed to authenticate against the device itself or against other devices sharing the same credentials, allowing the attacker to access and tamper with the device's data and to disrupt its operations.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:L/SA:L
CVSS Score: 5.3

Product Status

Vendor Nozomi Networks
Product Guardian
Versions Default: unaffected
  • affected from 0 to 26.3.0 (excl.)
Vendor Nozomi Networks
Product CMC
Versions Default: unaffected
  • affected from 0 to 26.3.0 (excl.)
Vendor Nozomi Networks
Product Arc
Versions Default: unaffected
  • affected from 0 to 2.7.0 (excl.)

Solutions

Upgrade Guardian/CMC to v26.3.0 or later. Upgrade Arc to v2.7.0 or later.

Credits

  • This issue was found by Stefano Balzarotti of Nozomi Networks and Andrea Palanca of Nozomi Networks Product Security team during an internal investigation. finder

References

Problem Types

  • CWE-671 Lack of Administrator Control over Security CWE

Impacts

  • CAPEC-94 Adversary in the Middle (AiTM)