GHSA-pxq6-2prw-chj9 CVE-2026-33997 GO-2026-4883
Moby has an Off-by-one error in its plugin privilege validation
- Severity
- 6.8 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 0.40%
- Chance of exploitation in the next 30 days. Higher than 34.43% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-193 Off-by-one Error
- Fix
2.0.0-beta.8- Upgrade github.com/moby/moby/v2 to this version or later
Description
Summary
A security vulnerability has been detected that allows plugins privilege validation to be bypassed during docker plugin install. Due to an error in the daemon's privilege comparison logic, the daemon may incorrectly accept a privilege set that differs from the one approved by the user.
Plugins that request exactly one privilege are also affected, because no comparison is performed at all.
Impact
If plugins are not in use, there is no impact.
When a plugin is installed, the daemon computes the privileges required by the plugin's configuration and compares them with the privileges approved during installation. A malicious plugin can exploit this bug so that the daemon accepts privileges that differ from what was intended to be approved.
Anyone who depends on the plugin installation approval flow as a meaningful security boundary is potentially impacted.
Depending on the privilege set involved, this may include highly sensitive plugin permissions such as broad device access.
For consideration: exploitation still requires a plugin to be installed from a malicious source, and Docker plugins are relatively uncommon. Docker Desktop also does not support plugins.
Workarounds
If unable to update immediately:
- Do not install plugins from untrusted sources
- Carefully review all privileges requested during
docker plugin install - Restrict access to the Docker daemon to trusted parties, following the principle of least privilege
- Avoid relying on plugin privilege approval as the only control boundary for sensitive environments
Credits
- Reported by Cody (c@wormhole.guru, PGP 0x9FA5B73E)
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/docker/docker | all versions |
No fix yet |
| github.com/moby/moby | all versions |
No fix yet |
| github.com/moby/moby/v2 | < 2.0.0-beta.8 |
2.0.0-beta.8 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/moby/moby/v2 Go → 2.0.0-beta.8
- go
go get github.com/moby/moby/v2@v2.0.0-beta.8 && go mod tidy
Severity breakdown
CVSS 3.1 6.8
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Weakness
CWE-193: Off-by-one Error
A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.
How to prevent it
- Implementation: When copying character arrays or using character manipulation methods, the correct size parameter must be used to account for the null terminator that needs to be added at the end of the array. Some examples of functions susceptible to this weakness in C include strcpy(), strncpy(), strcat(), strncat(), printf(), sprintf(), scanf() and sscanf().
References
Advisories
Packages
Other links
- github.com/moby/moby/security/advisories/GHSA-pxq6-2prw-chj9
- github.com/moby/moby/commit/f4d6f25bf0c3fa12d4968320a45685947756a22a
- docs.docker.com/engine/extend/legacy_plugins
- github.com/moby/moby/releases/tag/docker-v29.3.1
- access.redhat.com/errata/RHSA-2026:21769
- access.redhat.com/errata/RHSA-2026:22347
- access.redhat.com/errata/RHSA-2026:23345
- access.redhat.com/security/cve/CVE-2026-33997
- bugzilla.redhat.com/show_bug.cgi
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33997.json
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-rg2x-37c3-w2rh Docker: Race condition in docker cp allows bind mount redirection to host path | High | Also affects github.com/docker/docker |
| GHSA-vp62-88p7-qqf5 Docker: Race condition in docker cp allows creation of arbitrary empty files on the host via symlink swap | Medium | Also affects github.com/docker/docker |
| GHSA-x86f-5xw2-fm2r Docker: `PUT /containers/{id}/archive` executes container binary on the host | High | Also affects github.com/docker/docker |
| GO-2026-4887 Moby has AuthZ plugin bypass when provided oversized request bodies | High | Also affects github.com/docker/docker |
| GHSA-4vq8-7jfc-9cvp Moby firewalld reload removes bridge network isolation | Medium | Also affects github.com/docker/docker |
| GHSA-x4rx-4gw3-53p4 Moby firewalld reload makes published container ports accessible from remote hosts | Medium | Also affects github.com/docker/docker |
| GHSA-v23v-6jw2-98fq Authz zero length regression | Critical | Also affects github.com/docker/docker |
| GHSA-xmmx-7jpf-fx42 Moby (Docker Engine) is vulnerable to Ambiguous OCI manifest parsing | Low | Also affects github.com/docker/docker |
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