nats-server: Improper Authentication
CVE-2025-30215 is a critical-severity improper authentication vulnerability in nats-server from Nats-io, with a CVSS 3.1 base score of 9.6 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected nats-server versions: >= 2.2.0, < 2.10.27; >= 2.11.0-RC.1, < 2.11.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.61% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of nats-server you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Nats-io | nats-server | >= 2.2.0, < 2.10.27; >= 2.11.0-RC.1, < 2.11.1 | 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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- NoneNo data is disclosed.
- 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:L/UI:N/S:C/C:N/I:H/A:H. Scored by CNA (github.com).
Official description
NATS-Server is a High-Performance server for NATS.io, the cloud and edge native messaging system. In versions starting from 2.2.0 but prior to 2.10.27 and 2.11.1, the management of JetStream assets happens with messages in the $JS. subject namespace in the system account; this is partially exposed into regular accounts to allow account holders to manage their assets. Some of the JS API requests were missing access controls, allowing any user with JS management permissions in any account to perform certain administrative actions on any JS asset in any other account. At least one of the unprotected APIs allows for data destruction. None of the affected APIs allow disclosing stream contents. This vulnerability is fixed in v2.11.1 or v2.10.27.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in nats-server
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Authentication vulnerabilities
- 8.2 High severity
- 9.3 Critical severity
- 8.2 High severity
- 9.1 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
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