Auth bypass in Plastic Labs Honcho
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.
Vulnerability class: Broken Access Control
Published .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- hackmd.io/@haind/honcho-scoped-jwt-workspace-config-disclosure (third-party-advisory)
- github.com/plastic-labs/honcho/blob/608aec8a928da13c540262ed980c569448fb53ab/sr… (technical-description)
- github.com/plastic-labs/honcho/blob/608aec8a928da13c540262ed980c569448fb53ab/sr… (technical-description)
- github.com/plastic-labs/honcho/blob/608aec8a928da13c540262ed980c569448fb53ab/sr… (technical-description)
- github.com/plastic-labs/honcho (product)
- www.vulncheck.com/advisories/plastic-labs-honcho-through-3.3.0-incorrect-author… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-108711?
- CVE-2026-108711 is a medium-severity vulnerability in Plastic Labs Honcho, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2026-10-11.
- How severe is CVE-2026-108711?
- Medium severity. CVSS v3 base score is 4.3 out of 10.