moby: Off-by-one Error
CVE-2026-33997 is a high-severity off-by-one error vulnerability in moby, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected moby versions: < 29.3.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Engine to 29.3.1 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Moby | moby | < 29.3.1 | Not stated |
| Red Hat | Multicluster Global Hub 1.4.5 | Not specified in the record | Not stated |
| Red Hat | Multicluster Global Hub 1.6.5 | Not specified in the record | Not stated |
| Red Hat | Red Hat multicluster global hub 1.5.3 | Not specified in the record | Not stated |
| Red Hat | Multicluster Engine for Kubernetes | Not specified in the record | Not stated |
| Red Hat | OpenShift Service Mesh 2 | Not specified in the record | Not stated |
| Red Hat | Red Hat Advanced Cluster Management for Kubernetes 2 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Virtualization 4 | Not specified in the record | Not stated |
| Docker | Engine | before 29.3.1 | 29.3.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.8 | Medium | CNA (github.com) |
| CVSS 3.1 | 8.1 | High | NVD |
| CVSS 3.1 | 8.4 | High | CNA |
Official description
Moby is an open source container framework. Prior to version 29.3.1, 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. This issue has been patched in version 29.3.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: 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 developers prevent this class of flaw
- 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().
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/moby/moby/releases/tag/docker-v29.3.1Release Notes
Other references
Other vulnerabilities in moby
- 7.7 High severity
- 7.0 High severity
- 7.6 High severity
- 7.2 High severity
- 7.8 High severity
- 9.9 Critical severity
Recent Off-by-one Error vulnerabilities
- 7.8 High severity
- 7.1 High severity
- 7.8 High severity
- 8.4 High severity
- 7.5 High severity
- 9.8 Critical severity
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