CVE-2026-108711

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.

CVSS 4.0

5.3CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

4.3CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 19% of CVEs (scores of 2026-10-25)

CWE

CWE-863

Published

2026-10-11

Modified

2026-10-16

Record from

the NVD, synced 2026-10-19

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

Check your stackJSON