Guardian: Improper Verification of Cryptographic Signature
CVE-2026-33923 is a high-severity improper verification of cryptographic signature vulnerability in Guardian from Nozomi Networks, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. The record lists version 26.4.0 as the first without the flaw, so updating Guardian to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.23% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Guardian to 26.4.0 or a later version.
- Update CMC to 26.4.0 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Nozomi Networks | Guardian | before 26.4.0 | 26.4.0 |
| Nozomi Networks | CMC | before 26.4.0 | 26.4.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- HighAdministrator-level access is required first.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (nozominetworks.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.5 | High | CNA (nozominetworks.com) |
| CVSS 3.1 | 7.2 | High | CNA (nozominetworks.com) |
Official description
A signature verification vulnerability was discovered in the update installation functionality due to inconsistent validation of the update bundle contents. An attacker with administrative privileges can remotely supply a crafted update bundle that passes signature verification but runs an unsigned script when the bundle is installed. The script runs with root privileges, allowing the attacker to read or modify sensitive data, change the appliance configuration, or shut down the appliance.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
References
Other references
Other vulnerabilities in Guardian
- 7.2 High severity
- 7.5 High severity
- 7.4 High severity
- 8.1 High severity
- 7.5 High severity
- 7.1 High severity
Recent Improper Verification of Cryptographic Signature vulnerabilities
- 7.4 High severity
- 7.4 High severity
- 8.4 High severity
- 7.5 High severity
- 7.5 High severity
- 7.1 High severity
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