---
id: CVE-2026-44393
aliases:
  - GHSA-76qh-xr7q-h39m
title: >-
  OpenStack oslo.messaging does not verify RabbitMQ broker hostname during TLS
  handshake
summary: >-
  OpenStack oslo.messaging does not verify RabbitMQ broker hostname during TLS
  handshake
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
vendor: oslo-messaging
product: oslo-messaging
ecosystem: pip
affected:
  - 'oslo-messaging >= 1.0.0, <= 17.3.0'
published: '2026-06-04'
updated: '2026-07-15'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-76qh-xr7q-h39m'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-44393'
  - url: 'https://access.redhat.com/security/cve/CVE-2026-44393'
  - url: 'https://bugs.launchpad.net/oslo.messaging/+bug/2150316'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2484835'
  - url: 'https://github.com/openstack/oslo.messaging'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44393.json
  - url: 'https://wiki.openstack.org/wiki/OSSN/OSSN-0096'
tags:
  - osv
  - pip
epss: 0.00281
epssPercentile: 0.18359
ingestedAt: '2026-07-16T18:59:41.514Z'
---

## Overview

An issue was discovered in OpenStack oslo.messaging 1.0.0 through 17.3.0. The oslo.messaging RabbitMQ driver does not perform TLS hostname verification when connecting to the message broker. When ssl_ca_file is configured, the driver enables certificate chain validation but does not pass the expected broker hostname into the underlying TLS stack. Any certificate signed by the deployment CA is accepted regardless of hostname, allowing an attacker who can intercept control-plane traffic to impersonate the RabbitMQ broker and perform a man-in-the-middle attack on RPC and notification traffic. All OpenStack services using oslo.messaging with RabbitMQ over TLS are affected.

## Affected packages

- `oslo-messaging >= 1.0.0, <= 17.3.0`

## Remediation

Refer to the advisory for the patched release.