External risk intelligence

Apache Karaf Config Directory Traversal Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-91012

The vulnerability requires the attacker to already possess the 'manager' role within the Apache Karaf environment to execute the malicious configuration updates. As this requires authenticated, privileged access to internal management interfaces rather than being exposed as a public-facing service for unauthenticated users, public internet exposure is uncommon.

Path Traversal

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory concerns a vulnerability in Apache Karaf that could allow an authenticated user with manager privileges to write to any file the Karaf process can access, potentially leading to unauthorized control of the system. The issue arises from how configuration updates are processed, which can be manipulated to target files outside designated directories.

Allows privileged users to write arbitrary files.
Confirms potential for elevated access and system takeover.
Verify if your Karaf environment uses manager roles.

Attack Path

How an attacker could exploit the issue

An attacker with "manager" role access can manipulate configuration files to gain elevated privileges or take over the entire container. This is achieved by exploiting how the system handles configuration updates, specifically by providing input that allows writing files outside the intended configuration directory. The vulnerability stems from insufficient validation of user-supplied file paths when updating configurations.

Requires authenticated manager role access.
Update configuration with controlled file paths.
Arbitrary file write leading to container takeover.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an authenticated user with "manager" privileges to write attacker-controlled content to any file the Karaf process can access. This includes sensitive configuration files that control user access and service behavior.

System configuration files.
Unrestricted file writes via input manipulation.
Container takeover or privilege escalation.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Apache Karaf `config` MBean and `config:*` shell commands are vulnerable if they allow arbitrary file writes. The teams likely responsible for addressing this include platform or application owners who manage Karaf instances, and potentially security teams for reviewing access controls and impact. The first step is to identify all Karaf instances, determine their reachability and business criticality, and confirm the owning team to plan remediation.

Platform or application owners should manage the issue.
Verify Karaf instance reachability and criticality.
Plan remediation based on identified risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

Free EASM Trial See How Signal Works

Frequently asked questions

What is Apache Karaf and why is it used?

Apache Karaf is a lightweight, OSGi-based runtime environment used to deploy and manage modular applications. It acts as a container, providing services like remote management, logging, and configuration management. Developers often use it to build robust, scalable Java applications that require granular control over installed features and system settings.

What does CWE-22 mean for CVE-2026-91012?

CWE-22 refers to Path Traversal, a weakness where software uses user-supplied input to construct a file path without sufficient validation. In the context of this CVE, the vulnerability allows an attacker to manipulate configuration inputs—either through directory navigation characters or absolute file paths—to escape the intended configuration directory and write data to arbitrary locations on the host system.

How does an attacker trigger this vulnerability?

An attacker must hold the 'manager' role within the Karaf environment to access the affected configuration management functions. By submitting a crafted configuration update via the shell or JMX interface, the user can force the process to overwrite sensitive system files. Simply interacting with the platform or having non-privileged access does not trigger this flaw; it requires specific, authenticated authorization to perform configuration updates.

Is this vulnerability relevant to my environment?

Halo Surface Signal indicates that exploitation is unlikely for most because it requires pre-existing, authenticated 'manager' access rather than unauthenticated public exposure. However, if your Karaf instance manages critical services or is reachable via internal network interfaces where the 'manager' role could be abused by an insider or compromised account, the risk to your container security is significant.

What are the first steps to address CVE-2026-91012?

Begin by identifying all Karaf instances within your infrastructure and determining who owns or manages them. Review your current access controls to verify which users or service accounts possess the 'manager' role and audit those permissions for necessity. Coordinate with your platform or application teams to monitor for updates and ensure these instances are protected against unauthorized configuration changes.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.