Netmaker: Improper Verification of Cryptographic Signature
CVE-2026-38651 is a high-severity improper verification of cryptographic signature vulnerability in Netmaker, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 1.5.0 as the first without the flaw, so updating Netmaker to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.35% 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 Netmaker to 1.5.0 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from NVD's product matching. 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
- NoneNo account or login is needed.
- 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
- LowLimited modification of data is possible.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N. Scored by CISA (ADP).
Official description
Authentication Bypass vulnerability exists in Netmaker versions prior to 1.5.0. The VerifyHostToken function in logic/jwts.go fails to validate the JWT signature when verifying host tokens. An attacker can forge a JWT signed with any arbitrary key and use it to impersonate any host in the network, gaining access to sensitive information
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: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Technical write-ups (may include proof of concept)
- zyenra.com/advisories/netmaker-jwt-verification-bypassExploit, Third Party Advisory
- zyenra.com/blog/netmaker-jwt-verification-bypassExploit, Third Party Advisory
- zyenra.com/advisories/netmaker-jwt-verification-bypass/Exploit, Third Party Advisory
Recent Improper Verification of Cryptographic Signature vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 7.3 High severity
- 9.1 Critical severity
- 8.1 High severity
- 8.1 High severity
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