CVE-2026-44242 | Micronaut Framework: Unbounded bundleCache in ResourceBundleMessageSource Allows Memory Exhaustion via Accept-Language Header

Micronaut Framework is a JVM-based full stack Java framework designed for building modular, easily testable JVM applications. Prior to 4.10.22, the bundleCache is keyed by (Locale, baseName) where the locale originates from the HTTP Accept-Language header. In applications that explicitly register a ResourceBundleMessageSource bean and serve HTML error responses, an unauthenticated attacker can exhaust heap memory by sending requests with large numbers of unique Accept-Language values, each causing a new entry in the unbounded bundleCache. This vulnerability is fixed in 4.10.22.

Published: 2026-05-12 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-44242 is rated Low Risk (18.8/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.21%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-44242

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.05% 0.21% +0.16%
2 2026-06-13 0.04% 0.05% +0.02%
3 2026-05-13 — 0.04% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-44242

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.7 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.2 1.4 [email protected]

Weakness enumeration for CVE-2026-44242

GitHub Security Advisory for CVE-2026-44242

GHSA-3rfq-4wpf-qqw3 · Severity: low · Ecosystem: maven — Micronaut has Unbounded `bundleCache` in `ResourceBundleMessageSource` that Allows Memory Exhaustion via `Accept-Language` Header

Affected software / configurations for CVE-2026-44242

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-44242

cvelogic Threat Intelligence