CVE-2026-34040: Moby: AuthZ plugin bypass with oversized request body
Summary
A security vulnerability has been detected that allows attackers to bypass authorization plugins (AuthZ) under specific circumstances. The base likelihood of this being exploited is low.
This is an incomplete fix for CVE-2024-41110.
Impact
If you don't use AuthZ plugins, you are not affected.
Using a specially-crafted API request, an attacker could make the Docker daemon forward the request to an authorization plugin without the body. The authorization plugin may allow a request which it would have otherwise denied if the body had been forwarded to it.
Anyone who depends on authorization plugins that introspect the request body to make access control decisions is potentially impacted.
Workarounds
If unable to update immediately: - Avoid using AuthZ plugins that rely on request body inspection for security decisions. - Restrict access to the Docker API to trusted parties, following the principle of least privilege.
Credits
- 1seal / Oleh Konko (@1seal) - Cody (c@wormhole.guru) - Asim Viladi Oglu Manizada (@manizada)
Resources
- CVE-2024-41110 / GHSA-v23v-6jw2-98fq
Other sources
Moby is an open source container framework. Prior to version 29.3.1, a security vulnerability has been detected that allows attackers to bypass authorization plugins (AuthZ). This issue has been patched in version 29.3.1.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-34040?
The severity of CVE-2026-34040 is low due to the specific conditions required for exploitation.
How do I fix CVE-2026-34040?
To fix CVE-2026-34040, upgrade to versions greater than 2.0.0-beta.8 of the affected software.
What software is affected by CVE-2026-34040?
CVE-2026-34040 affects versions below 2.0.0-beta.8 of GitHub repositories like github.com/moby/moby and github.com/docker/docker.
Can CVE-2026-34040 be exploited remotely?
Exploitation of CVE-2026-34040 requires local access, limiting its risk of remote exploitation.
Is there a workaround for CVE-2026-34040?
Currently, there are no known workarounds for CVE-2026-34040 other than upgrading the affected software.