micronaut-projects micronaut-core up to 4.10.21 Locale.forLanguageTag resource consumption

Summaryinfo

A vulnerability was found in micronaut-projects micronaut-core up to 4.10.21. It has been declared as problematic. This vulnerability affects the function Locale.forLanguageTag. The manipulation results in resource consumption. This vulnerability is reported as CVE-2026-44241. The attack can be launched remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in micronaut-projects micronaut-core up to 4.10.21. Affected is the function Locale.forLanguageTag. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. CVE summarizes:

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<String, DateTimeFormatter> 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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-44241 since 05/05/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 4.10.22 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Type

• Project Management Software

Vendor

• micronaut-projects

Name

• micronaut-core

Version

• 4.10.0
• 4.10.1
• 4.10.2
• 4.10.3
• 4.10.4
• 4.10.5
• 4.10.6
• 4.10.7
• 4.10.8
• 4.10.9
• 4.10.10
• 4.10.11
• 4.10.12
• 4.10.13
• 4.10.14
• 4.10.15
• 4.10.16
• 4.10.17
• 4.10.18
• 4.10.19
• 4.10.20
• 4.10.21

Website

• Product: https://github.com/micronaut-projects/micronaut-core/

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