Incorrect authorization in Plastic Labs Honcho exposes workspace data
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.
Summary
Plastic Labs Honcho through 3.3.0 contains an incorrect authorization flaw (CWE-863) in its workspace handling. A holder of a peer- or session-scoped API key can read workspace metadata and configuration, including custom_instructions, which should be limited to workspace or admin keys.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
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 get_or_create_workspace 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 custom_instructions, reserved for workspace or admin keys.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Plastic Labs | honcho | up to 3.3.0 | — | No fix listed | CNA |
- honcho VendorPlastic Labs Affected up to 3.3.0 Fixed in — No fix listed CNA
Remediation
No fixed version is listed for Plastic Labs Honcho.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Vendor assessments
Timeline
- 2026-10-11 Threatist record created from CVE-2026-108711
- 2026-10-11 Alias added: GHSA-xj43-ppg4-ghf5
- 2026-10-13 CISA SSVC decision points changed
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 CVSS score added · Red Hat
References
Other 4
- https://github.com/plastic-labs/honcho/blob/608aec8a928da13c540262ed980c569448fb53ab/src/routers/workspaces.py#L41-L72
- https://github.com/plastic-labs/honcho/blob/608aec8a928da13c540262ed980c569448fb53ab/src/security.py#L218-L225
- https://github.com/plastic-labs/honcho/blob/608aec8a928da13c540262ed980c569448fb53ab/src/crud/workspace.py#L112-L119
- https://github.com/plastic-labs/honcho
Sources
- CVE-2026-108711 · CVE Program
- CVE-2026-108711 · NVD
- FIRST EPSS
- GHSA-xj43-ppg4-ghf5 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-108711 · Red Hat security data · CC BY 4.0
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