CVE-2026-34040Public exploit

Authorization bypass via omitted oversized request bodies

Published Mar 31, 2026 · Updated Mar 31, 2026

Authorization bypass in Moby before 29.3.1 allows local users with Docker API access to execute requests denied by AuthZ plugins. In pkg/authorization/authz.go, drainBody treats bodies at least 1 MiB long as uninspectable and passes an empty body to the plugin while preserving the original stream for the daemon. Only deployments using AuthZ plugins that inspect request bodies are affected; a Docker API user can submit an otherwise-denied daemon action.

CVSS severity8.8
High
EPSS probability9.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in Moby before 29.3.1 allows local users with Docker API access to execute requests denied by AuthZ plugins. In pkg/authorization/authz.go, drainBody treats bodies at least 1 MiB long as uninspectable and passes an empty body to the plugin while preserving the original stream for the daemon. Only deployments using AuthZ plugins that inspect request bodies are affected; a Docker API user can submit an otherwise-denied daemon action.

The record

CVE
CVE-2026-34040
Published
Mar 31, 2026
Updated
Mar 31, 2026
Vendor
Moby Project
Product
Moby
Classifications
CWE-288, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 29.3.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Moby Project · Mobyversion=< 29.3.1

Published CVSS scores

8.8GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-288Authentication Bypass Using an Alternate Path or Channel
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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