---
id: "CVE-2026-12343"
kind: "vulnerability"
aliases: ["CVE-2026-12343"]
title: "IBM MQ Operator: crafted RFH2 header can crash queued pub/sub"
severity: "medium"
cvss: 6.5
epss: null
exploited: false
status: "open"
category: "vendor"
products: [{"name": "ibm mq operator", "fixed": [], "affected": ">= 2.0.0, <= 2.0.29", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": ">= 3.2.0, <= 3.2.29", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.3.0", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.4.0", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.4.1", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.5.0", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.5.1", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.5.2", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.5.3", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.6.0", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.6.1", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.6.2", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.6.3", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.6.4", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.7.0", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.7.1", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.7.2", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.8.0", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.8.1", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.9.0", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.9.1", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 3.9.2", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 4.0.0", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 4.0.1", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 4.0.2", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 4.0.3", "ecosystem": "vendor"}, {"name": "ibm mq operator", "fixed": [], "affected": "= 4.0.4", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.1.0", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.1.1", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.2.0", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.2.1", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.3.0", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.3.1", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.4.0", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.4.1", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.5.0", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.4.5.1", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 10.0.0.0", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 10.0.0.5", "ecosystem": "vendor"}, {"name": "ibm supplied mq advanced container images", "fixed": [], "affected": "= 9.3.0.0", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["ibm-mq", "kubernetes", "messaging", "vendor"]
not_affected_if: ["unaffected-version"]
published_at: "2026-10-19T17:17:17+00:00"
first_seen_at: "2026-10-23T21:57:18+00:00"
updated_at: "2026-10-25T03:55:49+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-12343", "first_seen_at": "2026-10-23T21:57:18+00:00"}]
---

# IBM MQ Operator: crafted RFH2 header can crash queued pub/sub

IBM MQ Operator does not properly validate RFH2 message header fields in queued publish/subscribe operations. An authenticated attacker can send a crafted message to cause a denial of service.

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

## Affected

- vendor:ibm mq operator affected >= 2.0.0, <= 2.0.29 fixed ?
- vendor:ibm mq operator affected >= 3.2.0, <= 3.2.29 fixed ?
- vendor:ibm mq operator affected = 3.3.0 fixed ?
- vendor:ibm mq operator affected = 3.4.0 fixed ?
- vendor:ibm mq operator affected = 3.4.1 fixed ?
- vendor:ibm mq operator affected = 3.5.0 fixed ?
- vendor:ibm mq operator affected = 3.5.1 fixed ?
- vendor:ibm mq operator affected = 3.5.2 fixed ?
- vendor:ibm mq operator affected = 3.5.3 fixed ?
- vendor:ibm mq operator affected = 3.6.0 fixed ?
- vendor:ibm mq operator affected = 3.6.1 fixed ?
- vendor:ibm mq operator affected = 3.6.2 fixed ?
- vendor:ibm mq operator affected = 3.6.3 fixed ?
- vendor:ibm mq operator affected = 3.6.4 fixed ?
- vendor:ibm mq operator affected = 3.7.0 fixed ?
- vendor:ibm mq operator affected = 3.7.1 fixed ?
- vendor:ibm mq operator affected = 3.7.2 fixed ?
- vendor:ibm mq operator affected = 3.8.0 fixed ?
- vendor:ibm mq operator affected = 3.8.1 fixed ?
- vendor:ibm mq operator affected = 3.9.0 fixed ?
- vendor:ibm mq operator affected = 3.9.1 fixed ?
- vendor:ibm mq operator affected = 3.9.2 fixed ?
- vendor:ibm mq operator affected = 4.0.0 fixed ?
- vendor:ibm mq operator affected = 4.0.1 fixed ?
- vendor:ibm mq operator affected = 4.0.2 fixed ?
- vendor:ibm mq operator affected = 4.0.3 fixed ?
- vendor:ibm mq operator affected = 4.0.4 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.1.0 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.1.1 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.2.0 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.2.1 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.3.0 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.3.1 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.4.0 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.4.1 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.5.0 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.4.5.1 fixed ?
- vendor:ibm supplied mq advanced container images affected = 10.0.0.0 fixed ?
- vendor:ibm supplied mq advanced container images affected = 10.0.0.5 fixed ?
- vendor:ibm supplied mq advanced container images affected = 9.3.0.0 fixed ?

## How to check

- Check the installed IBM MQ Operator version against the affected ranges in the sources: `2.0.0` to `2.0.29`, `3.2.0` to `3.2.29`, and `3.3.0` to `3.6.2` (listed specific releases).
- Confirm whether queued publish/subscribe is in use on affected queue managers (unknown from sources how to query this directly).

## Fix

- Upgrade IBM MQ Operator to a fixed release. The sources do not name the fixed versions; see the IBM security bulletin for CVE-2026-12343.

## Timeline

- 2026-10-23T21:57:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-12343

## From the sources

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.

---

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