CVE Intelligence
High

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

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.

Published Sep 8, 2026 · Updated Oct 15, 2026 · Sources: CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database, GitHub Security Advisories · CNA: Nozomi

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.16%
ahead of 5% of scored CVEs · Oct 14, 2026
Affects
Nozominetworks
Arc and 2 more
CVSS base
7.5
High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Nozominetworks Arc, Nozominetworks Cmc, Nozominetworks Guardian).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  5. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Nozominetworks Arc < 2.7.0 Vulnerable CVE Program (cve.org) e CISA ADP
Nozominetworks Cmc < 26.3.0 Vulnerable CVE Program (cve.org) e CISA ADP
Nozominetworks Guardian < 26.3.0 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
5.3 CVSS 4.0 Medium — — prodsec@nozominetworks.com via NIST National Vulnerability Database
5.3 CVSS 4.0 Medium — — Nozomi via CVE Program (cve.org) e CISA ADP
7.5 CVSS 3.1 High 1.6 5.3 prodsec@nozominetworks.com via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
7.5 CVSS 3.1 High — — Nozomi via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:L (score shown at the top: prodsec@nozominetworks.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-671

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Published → Awaiting Analysis
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 15, 2026
  • CVSS changed · 7.5
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record created in this database
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • CVE published
    Sep 8, 2026 · Nozomi

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 15, 2026 – Oct 15, 2026
  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

4 on the record

Elsewhere on this site

Nozominetworks
every CVE for this vendor
CWE-671
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-33391 Incorrect authorization in Smart Polling configuration in Guardian/CMC before 26.3.0 Sep 8, 2026
  • CVE-2026-33388 Incorrect authorization in Credentials Manager in Guardian/CMC before 26.3.0 Sep 8, 2026
  • CVE-2026-33387 Insufficient sanitization of Dashboards in Guardian/CMC before 26.3.0 Sep 8, 2026
  • CVE-2026-33920 Cross-site request forgery in the Guardian/CMC login before 26.3.0 Sep 8, 2026
  • CVE-2026-33390 Incorrect privilege assignment for Arc sensors in Guardian/CMC before 26.2.0 Jul 9, 2026
  • CVE-2026-31983 Missing authentication in SSH keys synchronization endpoint in Guardian/CMC before 26.2.0 Jul 9, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-33389 is "Disabled and non-configurable certificate/host key validation in Smart Polling in Guardian/CMC before 26.3.0 and Arc before v2.7.0", rated High. It affects Arc (Nozominetworks); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.16% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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