# CVE-2026-12670: IBM MQ denial of service in character set conversion

Source: https://junglewise.ai/threats/cve-2026-12670-ibm-mq-could-allow-an-authenticated-attacker-to-cause-a-denial-of  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-19. Updated: 2026-10-19  
License: CC BY 4.0 with a link back

CVE-2026-12670 · Severity: medium · CVSS 5.3 · Published 2026-10-19

IBM MQ is a messaging system that allows applications to communicate reliably across networks. An authenticated attacker can send a specially crafted message that causes excessive memory consumption during character set conversion, resulting in a denial of service that disrupts message processing and application availability.

Technologies: [IBM Mq](https://junglewise.ai/threats/technologies/mq). Vendors: [IBM](https://junglewise.ai/threats/vendors/ibm).

## Quick answers

**Is CVE-2026-12670 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-12670 being exploited in the wild.

**How severe is CVE-2026-12670?** Medium severity, with a CVSS score of 5.3, published 19 October 2026.

**Which products and versions are affected?** IBM MQ.

**Is there a fix for CVE-2026-12670?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-12670 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-12670?** Check whether you run IBM Mq. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A denial of service vulnerability in IBM MQ's character set conversion logic allows an authenticated attacker to trigger excessive memory operations by sending a specially crafted message. The vulnerability requires prior authentication to the MQ system. A successful exploit prevents the queue manager from processing messages, causing service unavailability.

## Affected products

- IBM MQ

## Timeline

- 2026-10-19: disclosed

## References

- [https://www.ibm.com/support/pages/node/7292667](https://www.ibm.com/support/pages/node/7292667)

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