CVE-2026-88021 (CVSS 7.1)

Description

Consul and Consul Enterprise are vulnerable to an authorization bypass in the Connect service mesh that may allow a service to reach a destination it is not authorized to access. When building Envoy RBAC rules to enforce Connect intentions, Consul did not correctly escape certain characters in service names, namespaces, and partitions, causing the generated authorization rules to match more broadly than intended. This vulnerability (CVE-2026-88021) is fixed in Consul 2.0.4 and Consul Enterprise 1.21.18, 1.22.12 and 2.0.4.

Is your site exposed to CVE-2026-88021?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-185 CWE-185

References

Other References

https://discuss.hashicorp.com/t/hcsec-2026-37-consul-vulnerable-to-an-authorization-bypass-in-the-connect-service-mesh/77739

Frequently Asked Questions

What is CVE-2026-88021? +

Consul and Consul Enterprise are vulnerable to an authorization bypass in the Connect service mesh that may allow a service to reach a destination it is not authorized to access. When building Envoy RBAC rules to enforce Connect intentions, Consul did not correctly escape certain characters in service names, namespaces, and partitions, causing the generated authorization rules to match more broadly than intended. This vulnerability (CVE-2026-88021) is fixed in Consul 2.0.4 and Consul Enterprise 1.21.18, 1.22.12 and 2.0.4. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2026-88021? +

CVE-2026-88021 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-88021? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2024-52289 9.8

authentik is an open-source identity provider. Redirect URIs in the OAuth2 provider in authentik are checked by RegEx comparison. When …

CVE-2026-4296 8.8

An incorrect regular expression vulnerability was identified in GitHub Enterprise Server that allowed an attacker to bypass OAuth redirect URI …

CVE-2024-2223 8.1

An Incorrect Regular Expression vulnerability in Bitdefender GravityZone Update Server allows an attacker to cause a Server Side Request Forgery …

CVE-2025-54365 7.5

fastapi-guard is a security library for FastAPI that provides middleware to control IPs, log requests, detect penetration attempts and more. …

CVE-2025-20139 7.5

A vulnerability in chat messaging features of Cisco Enterprise Chat and Email (ECE) could allow an unauthenticated, remote attacker to …

CVE-2026-25542 6.5

Tekton Pipelines project provides k8s-style resources for declaring CI/CD-style pipelines. From 0.43.0 to 1.11.0, trusted resources verification policies match a …

CVE-2026-88021