A recently disclosed high-severity security flaw in Apache ActiveMQ Classic has come under active exploitation in the wild, per the U.S. Cybersecurity and Infrastructure Security Agency (CISA).
To that end, the agency has added the vulnerability, tracked as CVE-2026-34197 (CVSS score: 8.8), to its Known Exploited Vulnerabilities (KEV) catalog, requiring Federal Civilian Executive Branch (FCEB) agencies to apply the fixes by April 30, 2026.
CVE-2026-34197 has been described as a case of improper input validation that could lead to code injection, effectively allowing an attacker to execute arbitrary code on susceptible installations. According to Horizon3.ai's Naveen Sunkavally, CVE-2026-34197 has been "hiding in plain sight" for 13 years.
"An attacker can invoke a management operation through ActiveMQ's Jolokia API to trick the broker into fetching a remote configuration file and running arbitrary OS commands," Sunkavally added.
"The vulnerability requires credentials, but default credentials (admin:admin) are common in many environments. On some versions (6.0.0–6.1.1), no credentials are required at all due to another vulnerability, CVE-2024-32114, which inadvertently exposes the Jolokia API without authentication. In those versions, CVE-2026-34197 is effectively an unauthenticated RCE."
The vulnerability impacts the following versions -
- Apache ActiveMQ Broker (org.apache.activemq:activemq-broker) before 5.19.4
- Apache ActiveMQ Broker (org.apache.activemq:activemq-broker) 6.0.0 before 6.2.3
- Apache ActiveMQ (org.apache.activemq:activemq-all) before 5.19.4
- Apache ActiveMQ (org.apache.activemq:activemq-all) 6.0.0 before 6.2.3
Users are advised to upgrade to version 5.19.4 or 6.2.3, which addresses the issue. There are currently no details on how CVE-2026-34197 is being exploited in the wild, but SAFE Security, in a report published this week, revealed that threat actors are actively targeting exposed Jolokia management endpoints in Apache ActiveMQ Classic deployments.
Telemetry data gathered by Fortinet FortiGuard Labs has also uncovered dozens of exploitation attempts over the past couple of days, with the activity peaking on April 14, 2026.
The findings once again demonstrate that exploitation timelines continue to collapse as attackers pounce upon newly disclosed vulnerabilities at an alarmingly faster rate and breach systems before they can be patched.
Apache ActiveMQ is a popular target for attack, with flaws in the open-source message broker repeatedly exploited in various malware campaigns since 2021. In August 2025, a critical vulnerability in ActiveMQ (CVE-2023-46604, CVSS score: 10.0) was weaponized by unknown actors to drop a Linux malware called DripDropper.
"Given ActiveMQ’s role in enterprise messaging and data pipelines, exposed management interfaces present a high-impact risk, potentially enabling data exfiltration, service disruption, or lateral movement," SAFE Security said. "Organizations should audit all deployments for externally accessible Jolokia endpoints, restrict access to trusted networks, enforce strong authentication, and disable Jolokia where it is not required."
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