Consul: Incorrect Authorization
CVE-2026-87090 is a high-severity incorrect authorization vulnerability in Consul from HashiCorp, with a CVSS 3.1 base score of 8.3 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. The record lists version 2.0.4 as the first without the flaw, so updating Consul to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.37% 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 Consul to 2.0.4 or a later version.
- Update Consul Enterprise to 2.0.4 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| HashiCorp | Consul | 0.1.0 up to, but not including, 2.0.4 | 2.0.4 |
| HashiCorp | Consul Enterprise | 0.1.0 up to, but not including, 2.0.4 | 2.0.4 |
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
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data 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:L/UI:N/S:U/C:L/I:H/A:H. Scored by CNA (hashicorp.com).
Official description
Consul and Consul Enterprise are vulnerable to an authorization bypass in the catalog node-write path that may allow an authenticated attacker to delete another node's catalog registration and take over its node identity. An attacker with a token granting node-write permission on any single node name may exploit this issue if they can obtain the node ID of a node they do not control. This vulnerability (CVE-2026-87090) is fixed in Consul 2.0.4 and Consul Enterprise 1.21.18, 1.22.12 and 2.0.4.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How developers prevent this class of flaw
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework and the OWASP ESAPI Access Control feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
References
Other references
Other vulnerabilities in Consul
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
- 7.1 High severity
- 7.5 High severity
- 7.3 High severity
Recent Incorrect Authorization vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 9.1 Critical severity
- 8.3 High severity
- 8.8 High severity
- 7.1 High severity
Spotted an error? Tell us.