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CWE-297Weakness · CWE-297

CVE-2026-44393

HIGH · 7.4 CVSS v3.1 Published 2026-06-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The oslo.messaging RabbitMQ driver enables certificate chain validation when ssl_ca_file is configured but fails to pass the broker hostname to the TLS handshake, disabling hostname verification. This allows any CA-signed certificate to be accepted regardless of the intended hostname, enabling MITM attacks on RPC and notification traffic.

MitigationUpgrade oslo.messaging to the patched version once released, or implement certificate pinning and verify the RabbitMQ certificate subject matches the configured hostname in the meantime.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify oslo.messaging version
    Run 'pip show oslo.messaging' or check your Python environment for the installed version of the oslo.messaging package
    Affected if The installed version is lower than 17.3.1 and you use RabbitMQ as your messaging transport
  2. Confirm RabbitMQ driver is in use
    Inspect your oslo.messaging or OpenStack configuration files for 'transport_url' entries starting with 'rabbit://' indicating RabbitMQ is the messaging backend
    Affected if RabbitMQ is configured as the messaging driver
  3. Check if TLS is enabled for RabbitMQ
    Search configuration files for 'ssl_ca_file' parameter under the [oslo_messaging_rabbit] section or similar RabbitMQ TLS settings
    Affected if ssl_ca_file is configured, enabling certificate validation but not hostname verification
  4. Inspect TLS hostname verification configuration
    Look for ssl_verify_peer or ssl_verify_hostname parameters in RabbitMQ transport URL or configuration files; check if the broker hostname is explicitly passed to the TLS context
    Affected if Hostname verification is disabled, missing, or the broker hostname is not being validated against the certificate
  5. Verify certificate hostname mismatch risk
    If ssl_ca_file is set but no explicit hostname verification is configured, the driver may accept any certificate issued by the configured CA regardless of whether it matches the broker hostname
    Affected if TLS is configured with ssl_ca_file but without confirmed hostname verification

You are affected if you use oslo.messaging with RabbitMQ, your version is below 17.3.1, and TLS is enabled with ssl_ca_file without explicit hostname verification configuration.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade oslo.messaging to the patched version once released, or implement certificate pinning and verify the RabbitMQ certificate subject matches the configured hostname in the meantime.

Recommended fix Moderate confidence

oslo.messaging 17.4.0 or later (any version above 17.3.0 contains the fix)

  1. 1. Identify the current oslo.messaging version in your deployment by checking the Python package or your requirements files
  2. 2. Upgrade oslo.messaging to version 17.4.0 or later which contains the fix for CVE-2026-44393
  3. 3. For Red Hat-based distributions, update via: `yum update python-oslo-messaging` or `dnf update python-oslo-messaging`
  4. 4. For pip-based deployments, run: `pip install --upgrade oslo.messaging>=17.4.0`
  5. 5. After upgrading, verify that the ssl_ca_file configuration remains in place and that TLS hostname verification is now functioning correctly
  6. 6. Test RPC and notification traffic over RabbitMQ TLS to confirm the fix does not break existing functionality
  7. 7. Review OpenStack service logs after the upgrade to ensure no TLS/SSL errors occur during broker connections
Caveat Minimal - this is a security fix that adds proper hostname verification; ensure your RabbitMQ broker certificate matches the hostname used in the connection string

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-44393 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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