What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-11 · updated 2026-10-16
• Weakness: CWE-863

Description

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.

Affected products

• Plastic Labs honcho: through 3.3.0

References

• https://github.com/plastic-labs/honcho
• https://github.com/plastic-labs/honcho/blob/608aec8a928da13c540262ed980c569448fb53ab/src/crud/workspace.py#L112-L119
• 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://hackmd.io/@haind/honcho-scoped-jwt-workspace-config-disclosure
• https://www.vulncheck.com/advisories/plastic-labs-honcho-through-3.3.0-incorrect-authorization-via-post-v3-workspaces

Get alerted when CVE-2026-108711 or the next vulnerability affects your stack