CVE-2023-46604: Apache ActiveMQ Deserialization of Untrusted Data Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Apache ActiveMQ. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2023-11-02, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2023-11-23; treat that as the outer limit, not the target. CISA also lists it as known to be used in ransomware campaigns.
• EPSS 99.9%, percentile 100.0: FIRST’s model estimates a 99.9% chance of exploitation activity in the next 30 days, higher than 100.0% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes org.apache.activemq:activemq-client (Maven) < 5.15.16, fixed in 5.15.16; org.apache.activemq:activemq-client (Maven) >= 5.16.0, < 5.16.7, fixed in 5.16.7; org.apache.activemq:activemq-client (Maven) >= 5.17.0, < 5.17.6, fixed in 5.17.6; org.apache.activemq:activemq-client (Maven) >= 5.18.0, < 5.18.3, fixed in 5.18.3. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

Apache ActiveMQ is vulnerable to Remote Code Execution.The vulnerability may allow a remote attacker with network access to a broker to run arbitrary shell commands by manipulating serialized class types in the OpenWire protocol to cause the broker to instantiate any class on the classpath.

Users are recommended to upgrade to version 5.15.16, 5.16.7, 5.17.6, or 5.18.3, which fixes this issue.

CISA’s summary

Apache ActiveMQ contains a deserialization of untrusted data vulnerability that may allow a remote attacker with network access to a broker to run shell commands by manipulating serialized class types in the OpenWire protocol to cause the broker to instantiate any class on the classpath.

Weakness type: CWE-502.

Product: Apache ActiveMQ · Assigned by: apache · Published: 2023-10-27

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2023-11-02; federal due date 2023-11-23. Known ransomware use: Known.
• CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
• CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 99.89% probability of exploitation activity in the next 30 days; percentile 100.0.

Timeline

• 2023-10-27 — CVE record published by apache
• 2023-10-27 — GitHub-reviewed advisory GHSA-crg9-44h2-xw35 published (critical)
• 2023-11-02 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2023-11-23 — CISA remediation deadline for US federal agencies
• 2025-11-03 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. activemq.apache.org activemq.apache.org

Vulnerability records

1. GitHub Advisory GHSA-crg9-44h2-xw35 github.com
2. CVE.org record CVE-2023-46604 cve.org
3. NVD entry CVE-2023-46604 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

Other references from the CVE record and advisory

1. openwall.com openwall.com
2. security.netapp.com security.netapp.com
3. packetstormsecurity.com packetstormsecurity.com
4. lists.debian.org lists.debian.org
5. seclists.org seclists.org
6. lists.debian.org lists.debian.org
7. activemq.apache.org activemq.apache.org
8. issues.apache.org issues.apache.org
9. openwall.com openwall.com
10. github.com github.com
11. github.com github.com
12. packetstormsecurity.com packetstormsecurity.com
13. github.com github.com
14. github.com github.com
15. github.com github.com
16. github.com github.com

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