CVE-2026-108711: Plastic Labs Honcho through 3.3.0 Incorrect Authorization via POST /v3/workspaces

Q: Who can exploit this issue?

An attacker needs a valid peer-scoped or session-scoped API key and knowledge of the parent workspace name. The issue does not describe unauthenticated exploitation.

Q: What information can be disclosed?

The affected endpoint can return workspace metadata and configuration that should be limited to workspace or admin keys. This includes custom_instructions.

Q: Which endpoint and request condition are involved?

The issue is triggered through POST /v3/workspaces when the caller supplies the parent workspace name. The authorization check verifies only the workspace claim, allowing scoped keys to retrieve the parent workspace's data.

Q: How can an organization determine whether it may be affected?

Systems running Plastic Labs Honcho through 3.3.0 are within the stated affected range. Review use of peer-scoped and session-scoped API keys and requests to POST /v3/workspaces that reference parent workspace names.

Published Oct 11, 2026

Updated

Plastic Labs Honcho through 3.3.0 contains an incorrect authorization vulnerability that allows peer- or session-scoped API key holders to read workspace data because getorcreateworkspace checks only the workspace claim. Attackers can submit their parent workspace name to the POST /v3/workspaces endpoint to retrieve workspace metadata and configuration, including custominstructions, reserved for workspace or admin keys.

Affected Software

1 affected component

Plastic Labs Honcho<=3.3.0

Event History

Oct 11, 2026

CVE Published

via MITRE·12:19 PM

Data Sourced

via MITRE·12:19 PM

DescriptionSeverityWeakness

Data Sourced

via NVD·01:17 PM

DescriptionSeverityWeakness

Frequently Asked Questions

Who can exploit this issue?

An attacker needs a valid peer-scoped or session-scoped API key and knowledge of the parent workspace name. The issue does not describe unauthenticated exploitation.

What information can be disclosed?

The affected endpoint can return workspace metadata and configuration that should be limited to workspace or admin keys. This includes custom_instructions.

Which endpoint and request condition are involved?

The issue is triggered through POST /v3/workspaces when the caller supplies the parent workspace name. The authorization check verifies only the workspace claim, allowing scoped keys to retrieve the parent workspace's data.

How can an organization determine whether it may be affected?

Systems running Plastic Labs Honcho through 3.3.0 are within the stated affected range. Review use of peer-scoped and session-scoped API keys and requests to POST /v3/workspaces that reference parent workspace names.

CVE-2026-108711: Plastic Labs Honcho through 3.3.0 Incorrect Authorization via POST /v3/workspaces

Affected Software

Event History

Frequently Asked Questions

Who can exploit this issue?

What information can be disclosed?

Which endpoint and request condition are involved?

How can an organization determine whether it may be affected?

Company

Resources

Contact

Frequently Asked Questions

Who can exploit this issue?

What information can be disclosed?

Which endpoint and request condition are involved?

How can an organization determine whether it may be affected?