---
id: "CVE-2026-108946"
kind: "vulnerability"
aliases: ["CVE-2026-108946"]
title: "Apache ActiveMQ: authenticated clients can hijack other users' consumers and messages"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["activemq", "apache-activemq", "java", "message-broker", "runtime"]
not_affected_if: ["patched-version", "single-trusted-client", "unauthenticated-only-access"]
published_at: "2026-11-04T11:17:13+00:00"
first_seen_at: "2026-11-04T11:26:45+00:00"
updated_at: "2026-11-04T11:27:47+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-108946", "first_seen_at": "2026-11-04T11:26:45+00:00"}]
---

# Apache ActiveMQ: authenticated clients can hijack other users' consumers and messages

Apache ActiveMQ does not always check that connection, session and consumer ids belong to the client using them. An authenticated client can consume from another connection's temporary queue, tear down a victim's subscription, or delete an unacknowledged message.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed ActiveMQ version (`activemq --version` or the version in the broker's lib directory); versions from 6.0.0 before 6.3.3 and before 5.19.12 are affected.
- Check whether the broker is reachable by clients you do not fully trust.

## Fix

- Apache ActiveMQ 6.x: upgrade to `6.3.3` or later (`6.4.0` recommended)
- Apache ActiveMQ 5.x: upgrade to `5.19.12`
- Apache ActiveMQ KahaDB: same ranges as ActiveMQ, upgrade to `6.3.3`, `6.4.0`, or `5.19.12`

## Timeline

- 2026-11-04T11:26:45+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-108946

## From the sources

Improper input validation vulnerability in Apache ActiveMQ, Apache ActiveMQ KahaDB.



The ActiveMQ broker resolves connection, session and consumer state from ids that are user provided and in some scenarios does not validate that they ids are bound to that user. This allows an authenticated client to spoof another user's ids. This allows:





  *   an authenticated client consumes from another connection's temporary queue/topic by putting the victim's connection id in its own ConsumerId, bypassing the broker-side ownership check. 
  *  a duplicate ConsumerId registration is only logged, after which the attacker's RemoveInfo or disconnect tears down the victim's live subscription
  *  a forged MessageAck for the victim's ConsumerId permanently deletes an in-flight, unacknowledged message.








This issue affects Apache ActiveMQ: from 6.0.0 before 6.3.3, before 5.19.12; Apache ActiveMQ KahaDB: from 6.0.0 before 6.3.3, before 5.19.12.



Users are recommended to upgrade to version 6.4.0, 6.3.3, or 5.19.12, which fixes the issue.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_