Status: UPDATED | Advisory ID: CVE-2026-39304
| CVE | CVE-2026-39304 |
| CVSS Score / Version | 7.5 (High) / CVSS v3.1 |
| Updated | 2026-09-24 |
| CVSS Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| CVSS Prose | attack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is none; integrity impact is none; availability impact is high. |
| Affected products | Apache ActiveMQ and Apache ActiveMQ Broker |
| Classified as | CWE-400 (Uncontrolled Resource Consumption) |
| Exploitation prediction (EPSS) | 1.06% probability of exploitation in the next 30 days (63% percentile) -- FIRST.org's EPSS model. |
| Vendor | Product | Affected Versions | Patch Status |
|---|---|---|---|
| Apache | ActiveMQ | ||
| Apache | ActiveMQ Broker |
| Subsystems | General OT |
| Sectors | Multiple |
Denial of Service via Out of Memory vulnerability in Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ.
ActiveMQ NIO SSL transports do not correctly handle TLSv1.3 handshake KeyUpdates triggered by clients. This makes it possible for a client to rapidly trigger updates which causes the broker to exhaust all its memory in the SSL engine leading to DoS.
Note: TLS versions before TLSv1.3 (such as TLSv1.2) are broken but are not vulnerable to OOM. Previous TLS versions require a full handshake renegotiation which causes a connection to hang but not OOM. This is fixed as well.
This issue affects Apache ActiveMQ Client: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ Broker: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ: before 5.19.4, from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or 5.19.5, which fixes the issue.
Monitor Apache's web page for any future patch releases. See vendor advisory link below.