VulnerabilityPublished 20 Mar 2026

CVE-2026-33012: micronaut-core · Unthrottled Resource Allocation

Affects micronaut-coreSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High : upgrade to 4.10.17 soon.

Data as of 1 Nov 2026, 22:58 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.10.17

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade micronaut-core to 4.10.17.

Affected software

Product	Affected	Fixed in
micronaut-projectsmicronaut-core	Affected >=4.7.0 <4.10.17	Fixed in 4.10.17
Mavenio.micronaut/micronaut-core`pkg:maven/io.micronaut/micronaut-core`Other threats	Affected =4.7.0 =4.10.7	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The primary mitigation is to upgrade all affected Micronaut Framework instances to version 4.10.17 or later, where the unbounded cache issue is resolved. Until upgrades can be applied, organizations should implement strict input validation and sanitization to limit attacker influence on exception messages, reducing the ability to trigger large cache entries. Monitoring JVM heap usage and setting memory limits or alerts can help detect abnormal memory growth early. Employing runtime protections such as application-layer firewalls or rate limiting can reduce the volume of malicious requests triggering exceptions. Additionally, configuring JVM options to limit heap size and enable garbage collection logging can assist in identifying and mitigating memory exhaustion events. Developers should review custom error handling to avoid caching untrusted data and consider implementing cache size limits or eviction policies in application code. Regularly auditing dependencies and applying security patches promptly is essential to prevent exploitation.

Description

Micronaut Framework is a JVM-based full stack Java framework designed for building modular, easily testable JVM applications. Versions 4.7.0 through 4.10.16 used an unbounded ConcurrentHashMap cache with no eviction policy in its DefaultHtmlErrorResponseBodyProvider. If the application throws an exception whose message may be influenced by an attacker, (for example, including request query value parameters) it could be used by remote attackers to cause an unbounded heap growth and OutOfMemoryError, leading to DoS. This issue has been fixed in version 4.10.7.

Impact

This vulnerability can cause denial of service conditions in applications using affected Micronaut versions by exhausting heap memory through unbounded cache growth. Organizations relying on these versions for JVM-based microservices or web applications may experience application crashes or severe performance degradation, leading to service outages. This can disrupt business operations, degrade user experience, and potentially cause cascading failures in distributed systems. Since exploitation requires no authentication and can be triggered remotely, the attack surface is broad, increasing the risk of automated or targeted attacks. Although confidentiality and integrity are not directly impacted, the availability impact can be significant, especially for high-traffic or critical services. The lack of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as the vulnerability is publicly known and easily testable.

Summary

The vulnerability CVE-2026-33012 affects the Micronaut Framework's core component, specifically versions from 4.7.0 up to but not including 4.10.17. The root cause is the use of an unbounded ConcurrentHashMap cache in the DefaultHtmlErrorResponseBodyProvider, which lacks any eviction or size limits. When an application built on these versions throws exceptions, the exception messages—potentially influenced by attacker-controlled input such as query parameters—are cached indefinitely. This unbounded caching leads to continuous heap memory consumption growth, eventually causing an OutOfMemoryError and crashing the application or severely degrading its availability. The vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling). Exploitation requires no privileges or user interaction and can be performed remotely by sending crafted requests that trigger exceptions with attacker-controlled messages. The vulnerability does not impact confidentiality or integrity but results in high availability impact due to denial of service. The issue was publicly disclosed on March 20, 2026, with a CVSS 3.1 base score of 7.5 (high severity). The fix involves updating to Micronaut version 4.10.17 or later, where the cache is either bounded or properly evicted to prevent unbounded memory growth.

CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 20 Mar 2026, 05:39 UTC

WeaknessesCWE-770

Technical details

References

Community reviews

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