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High, CVSS 7.5

Micronaut has unbounded formattersCache in TimeConverterRegistrar that Allows Memory Exhaustion via Accept-Language Header

CVE-2026-44241GHSA-8hjv-92q9-g4xj

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (io.micronaut:micronaut-context 4.10.22, 3.10.6, 3.8.14), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2026-44241: 0.64% estimated exploitation activity in the next 30 days; percentile 50.51 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary 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 is structurally identical to the recently patched GHSA-2hcp-gjrf-7fhc (DefaultHtmlErrorResponseBodyProvider), but TimeConverterRegistrar.formattersCache was not covered by that fix. Details The vulnerable cache is declared in context/src/main/java/io/micronaut/runtime/converters/time/TimeConverterRegistrar.java at line 123: The getFormatter method at line 434 inserts into this map with no eviction or size limit: The attacker-controlled…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-8hjv-92q9-g4xj

Agent brief

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# Patch Next advisory brief: CVE-2026-44241

Advisory: Micronaut has unbounded `formattersCache` in `TimeConverterRegistrar` that Allows Memory Exhaustion via `Accept-Language` Header
IDs: CVE-2026-44241, GHSA-8hjv-92q9-g4xj
Record: https://patchnext.com/advisories/cve-2026-44241 (revision 1, source checked 26 Oct 2026, 16:54 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: io.micronaut:micronaut-context 4.10.22, 3.10.6, 3.8.14. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.micronaut:micronaut-context: affected >= 4.3.0, < 4.10.22; >= 3.10.0, < 3.10.6; < 3.8.14; fixed in 3.8.14, 4.10.22, 3.10.6

## Suggested inspection (read-only)
- Maven io.micronaut:micronaut-context: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on io.micronaut:micronaut-context.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-8hjv-92q9-g4xj (GitHub-reviewed advisory GHSA-8hjv-92q9-g4xj lists affected ranges: Maven io.micronaut:micronaut-context >=4.3.0 =3.10.0 =0 <3.8.14)

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