--- id: CVE-2026-44241 title: >- Micronaut Framework is a JVM-based full stack Java framework designed for building modular, easily testable JVM applications summary: >- Micronaut Framework is a JVM-based full stack Java framework designed for building modular, easily testable JVM applications. From 4.3.0 to before 4.10.22, 3.10.6, and 3.8.14, TimeConverterRegistrar caches DateTimeFormatter instances in … severity: high cvss: 7.5 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H' cwe: - CWE-400 published: '2026-05-12' updated: '2026-07-10' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-44241' references: - url: >- https://github.com/micronaut-projects/micronaut-core/commit/48f05ae8dc4157816fe0050c5cf730be7d44f8b3 label: security-advisories@github.com - url: >- https://github.com/micronaut-projects/micronaut-core/commit/c2048ab740c2efdfe227813f203176e0ef93f892 label: security-advisories@github.com - url: >- https://github.com/micronaut-projects/micronaut-core/commit/c6ca8782de7338732e887d090f38c9e941bcb284 label: security-advisories@github.com - url: 'https://github.com/micronaut-projects/micronaut-core/releases/tag/v3.10.6' label: security-advisories@github.com - url: 'https://github.com/micronaut-projects/micronaut-core/releases/tag/v3.8.14' label: security-advisories@github.com - url: 'https://github.com/micronaut-projects/micronaut-core/releases/tag/v4.10.22' label: security-advisories@github.com - url: >- https://github.com/micronaut-projects/micronaut-core/security/advisories/GHSA-8hjv-92q9-g4xj label: security-advisories@github.com - url: >- https://github.com/micronaut-projects/micronaut-core/security/advisories/GHSA-8hjv-92q9-g4xj label: 134c704f-9b21-4f2e-91b3-4a467353bcc0 tags: - nvd epss: 0.0072 epssPercentile: 0.51922 ingestedAt: '2026-07-10T01:55:23.211Z' --- ## Overview Micronaut Framework is a JVM-based full stack Java framework designed for building modular, easily testable JVM applications. From 4.3.0 to before 4.10.22, 3.10.6, and 3.8.14, TimeConverterRegistrar caches DateTimeFormatter instances in an unbounded ConcurrentHashMap whose key is derived from the @Format annotation pattern concatenated with the locale from the HTTP Accept-Language header. Because Locale.forLanguageTag() accepts arbitrary BCP 47 private-use extensions (en-x-a001, en-x-a002, …), an unauthenticated attacker can generate an unlimited number of unique cache keys by sending requests with novel locale tags, growing the cache until heap memory is exhausted and the JVM crashes. This vulnerability is fixed in 4.10.22, 3.10.6, and 3.8.14. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges.