kubero: Use of Hard-coded Cryptographic Key
CVE-2026-125370 is a critical-severity use of hard-coded cryptographic key vulnerability in kubero from Kubero-dev, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected kubero versions: 3.0.0 through 3.1.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.68% chance of exploitation within 30 days, higher than 53% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of kubero you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Kubero-dev | kubero | 3.0.0 through 3.1.1 | Not stated |
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
- 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
- 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:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.3 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 9.8 | Critical | CNA (vulncheck.com) |
Official description
Kubero 3.0.0 through 3.1.1 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to forge administrative JWTs by using a hardcoded fallback signing secret when JWT_SECRET is unset. Attackers can sign tokens with arbitrary role, userGroups and permissions claims, which JwtStrategy.validate() trusts without a database lookup, to take control of pipelines, applications, users and API tokens.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Hard-coded Cryptographic Key
The product uses a hard-coded, unchangeable cryptographic key.
How developers prevent this class of flaw
- Prevention schemes mirror that of hard-coded password storage.
More Use of Hard-coded Cryptographic Key vulnerabilities (CWE-321)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in kubero
- 9.1 Critical severity
Recent Use of Hard-coded Cryptographic Key vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 8.0 High severity
- 8.7 High severity
- 9.8 Critical severity
- 7.8 High severity
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