Incorrect authorization in Etherpad - #VU154091
Published: October 12, 2026
Vulnerability identifier: #VU154091
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-863
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to gain full administrative access to the HTTP API.
The vulnerability exists due to incorrect authorization in the HTTP API handler (APIHandler.ts) when validating bearer JWTs. A remote user can submit an ordinary authorization_code token whose sub claim matches a configured client_id, causing the token to be treated as a client_credentials token and bypass the admin claim check, to gain full administrative access to the HTTP API.
Only instances using Etherpad's built-in OIDC provider with configured API clients are affected.
Affected software
Etherpad
Remediation
Install security update from vendor's website.
Etherpad - update to 3.3.8