CVE-2026-42604 MEDIUM

CVE-2026-42604: Actual has an OpenID `client_secret` Disclosure via Broken Authorization Guard in `/openid/config`

Vendor Actualbudget
Product actual
Weakness CWE-863 · Incorrect authorization
Published June 12, 2026
Last update June 15, 2026
View on NVD All CVEs

CVSS base score

6.9/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U

What the vulnerability does

01Description

Actual is a local-first personal finance tool. The `POST /openid/config` endpoint in Actual Budget's sync-server versions <= 26.4.0 exposes the full OpenID Connect configuration—including the OAuth2 `client_secret`—to any caller who knows the bootstrap password. The endpoint also lacks authentication and rate limiting, making the bootstrap password brute-forceable. Version 26.5.0 fixes the issue.

Key dates

02Disclosure timeline

June 12, 2026 CVE published
June 15, 2026 Record updated