CVE-2026-12343 IBM MQ Denial of Service
An authenticated attacker can cause a denial of service in IBM MQ by exploiting improper validation of RFH2 message headers in publish/subscribe operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-12343?
CVE-2026-12343 is a medium-severity denial of service vulnerability in IBM MQ Advanced container images, published on 19 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
IBM MQ could allow an authenticated attacker to cause a denial of service due to improper validation of RFH2 message header fields in queued publish/subscribe operations.
Weakness: CWE-400
Which versions are affected by CVE-2026-12343?
It affects 2 products.
Products include Ibm Mq Operator, Ibm Supplied Mq Advanced Container Images.
How do I fix CVE-2026-12343?
No fix has been published for CVE-2026-12343 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-12343 being exploited?
There is no known exploitation of CVE-2026-12343 in the wild and no public exploit code.
Other vulnerabilities in IBM MQ Advanced container images
Sources
Also known as GHSA-4vv9-m5xv-x4cc.