High severity · published Sep 8, 2026
CVE-2026-33389
Disabled and non-configurable certificate/host key validation in Smart Polling in Guardian/CMC before 26.3.0 and Arc before v2.7.0
7.5
CVSS
0.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:L
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
Low
Availability
Low
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 6% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AR
Arc · Nozomi Networks
before 2.7.0 · source: vendor
CM
CMC · Nozomi Networks
before 26.3.0 · source: vendor
GU
Guardian · Nozomi Networks
before 26.3.0 · source: vendor
RA
RUGGEDCOM APE1808 · Siemens
0 · source: CISA
In the news
VulnerabilityHigh
Siemens RUGGEDCOM APE1808 Devices
View CSAF
Summary
Nozomi Networks has published information on vulnerabilities in Nozomi Guardian/CMC. This advisory lists the related Siemens Industrial products affected by these vulnerabilities. Siemens recommends to contact customer support to receive patch and update information.
The following versions of Siemens RUGGEDCOM APE1808 Devices are affected:
RUGGEDCOM APE1808 vers:all/* (CVE-2026-33387, CVE-2026-33388, CVE-2026-33389, CVE-2026-33391, CVE-2026-33920)
CVSS
Vendor
Equipment
v3 7.5
Siemens
RUGGEDCOM APE1808
4 Vulnerabilities
Improper Neutralization of Special Elements Used in a Template Engine, Incorrect Authorization, Lack of Administrator Control over Security, Cross-Site Request Forgery (CSRF)
Background
Critical Infrastructure Sectors: Critical Manufacturing, Transportation Systems, Energy, Healthcare and Public Health, Financial Services, Government Services and Facilities
Countries/Areas Deployed: Worldwide
Company Headquarters Location: Germany
Vulnerabilities
Expand All +
CVE-2026-33387
A template injection vulnerability was discovered in the Dashboards functionality due to improper validation of an input parameter. An authenticated user with the required privileges can define a dashboard containing a malicious payload, or a victim can be socially engineered into importing a malicious dashboard. When the victim views or imports the dashboard, the pay...
Oct 22, 2026·CISA Advisories
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33389
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33389
security.nozominetworks.com
https://security.nozominetworks.com/NN-2026:20-01
cert-portal.siemens.com
https://cert-portal.siemens.com/productcert/html/ssa-911336.html
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