Apache ActiveMQ Deserialization of Untrusted Data Vulnerability
Apache · ActiveMQ
The Java OpenWire protocol marshaller in Apache ActiveMQ deserializes untrusted data, letting attackers reach remote code execution through manipulated serialized class types in the OpenWire protocol. An attacker with network access to a Java-based OpenWire broker or client, and no authentication or user interaction, can cause the broker or client to instantiate any class on its classpath and thereby run arbitrary shell commands.
The Java OpenWire protocol marshaller is vulnerable to Remote Code Execution. This vulnerability may allow a remote attacker with network access to either a Java-based OpenWire broker or client to run arbitrary shell commands by manipulating serialized class types in the OpenWire protocol to cause either the client or the broker (respectively) to instantiate any class on the classpath. Users are recommended to upgrade both brokers and clients to version 5.15.16, 5.16.7, 5.17.6, or 5.18.3 which fixes this issue.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 4/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.How attackers get in
What they do
What can follow
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 6 days after disclosure. Public exploit code (PoC-in-GitHub) was available 1 day before disclosure.
- Public exploit codePoC-in-GitHub1 day before
- Disclosedday 0
- First seen exploitedVulnCheck KEV evidenceAdded to CISA KEVknown ransomware use; EU database agrees+6 days
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
Patch historyEarlier and later CVEs in the same code, in date order. It shows when a fix was bypassed or incomplete and which version finally fixed it.
7 fixes in activemq-client over 8 years. The latest fix listed for activemq-client is 6.2.4.
Fixes in activemq-clientMaven package, by fixed version. Earlier and later fixes in the same package, not necessarily the same bug.
- 5.14.5CVE-2015-75591 Aug 2019
- 5.15.6CVE-2018-1177510 Sep 2018
- 5.15.9CVE-2019-022228 Mar 2019
- 5.18.3CVE-2023-4660427 Oct 2023KEV
- 6.1.6CVE-2025-275337 May 2025
- 6.2.2CVE-2026-332277 Apr 2026
- 6.2.4CVE-2026-3930410 Apr 2026Latest listed
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
3 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 3Initial AccessTA0001
This vulnerability is exploited by a remote attacker who manipulates serialized class types in the OpenWire protocol to run arbitrary shell commands. This allows the adversary to execute remote code, leading to the download and installation of malware, such as the Kinsing malware and cryptocurrency miners, on Linux systems. Additionally, attackers have attempted to deploy ransomware, attributed to the HelloKitty ransomware family, on target systems.
ExecutionTA0002
Detection
0 rules for this CVE · 220 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2023-46604 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Exploit Public-Facing ApplicationT1190149 general rules
- Arcadyan Router Exploitationscriticaltest
- Citrix ADS Exploitation CVE-2020-8193 CVE-2020-8195criticaltest
- Citrix Netscaler Attack CVE-2019-19781criticaltest
- Confluence Exploitation CVE-2019-3398criticaltest
- CVE-2010-5278 Exploitation Attemptcriticaltest
- CVE-2020-0688 Exchange Exploitation via Web Logcriticaltest
- CVE-2020-10148 SolarWinds Orion API Auth Bypasscriticaltest
- CVE-2020-5902 F5 BIG-IP Exploitation Attemptcriticaltest
Unix ShellT1059.00419 general rules
- Linux Reverse Shell Indicatorcriticaltest
- AWS EC2 Startup Shell Script Changehightest
- Equation Group Indicatorshightest
- JexBoss Command Sequencehightest
- Shell Invocation via Env Command - Linuxhightest
- Suspicious Activity in Shell Commandshightest
- Suspicious Reverse Shell Command Linehightest
- Axios NPM Compromise Indicators - Linuxhighexperimental
Scheduled TaskT1053.00552 general rules
- Diamond Sleet APT Scheduled Task Creationcriticaltest
- OilRig APT Activitycriticaltest
- OilRig APT Registry Persistencecriticaltest
- OilRig APT Schedule Task Persistence - Securitycriticaltest
- OilRig APT Schedule Task Persistence - Systemcriticaltest
- Turla Group Commands May 2020criticaltest
- ChromeLoader Malware Executionhightest
- HackTool - Default PowerSploit/Empire Scheduled Task Creationhightest
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
Am I affected? What do I upgrade to?
From GitHub Security Advisories and OSV2 packages in 1 ecosystem. No single main package: each of these ships the affected code.
- Mavenorg.apache.activemq:activemq-clientAffected: 5.18.0 up to 5.18.3; 5.17.0 up to 5.17.6; 5.16.0 up to 5.16.7; All versions before 5.15.16Upgrade to 5.18.3 or later (older lines: 5.17.6, 5.16.7, 5.15.16)
- Mavenorg.apache.activemq:activemq-openwire-legacyAffected: 5.18.0 up to 5.18.3; 5.17.0 up to 5.17.6; 5.16.0 up to 5.16.7; 5.8.0 up to 5.15.16Upgrade to 5.18.3 or later (older lines: 5.17.6, 5.16.7, 5.15.16)
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 30, 202629 Oct 2026
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- 44 more on OTX