CVE-2023-36820: micronaut security has invalid IdTokenClaimsValidator logic on aud

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-10-09 · updated 2026-06-17
Weakness: CWE-284

Description

Micronaut Security is a security solution for applications. Prior to versions 3.1.2, 3.2.4, 3.3.2, 3.4.3, 3.5.3, 3.6.6, 3.7.4, 3.8.4, 3.9.6, 3.10.2, and 3.11.1, IdTokenClaimsValidator skips `aud` claim validation if token is issued by same identity issuer/provider. Any OIDC setup using Micronaut where multiple OIDC applications exists for the same issuer but token auth are not meant to be shared. This issue has been patched in versions 3.1.2, 3.2.4, 3.3.2, 3.4.3, 3.5.3, 3.6.6, 3.7.4, 3.8.4, 3.9.6, 3.10.2, and 3.11.1.

Affected products

micronaut-projects micronaut-security: before 3.1.2; from 3.2.0 before 3.2.4; from 3.3.0 before 3.3.2; from 3.4.0 before 3.4.3; from 3.5.0 before 3.5.3; from 3.6.0 before 3.6.6 — fixed in 3.1.2, 3.10.2, 3.2.4, 3.3.2, 3.4.3, 3.5.3

How to fix

Upgrade to a fixed version: micronaut-projects micronaut-security 3.1.2, 3.10.2, 3.2.4, 3.3.2. Check the vendor advisory for mitigations.

References

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