Auth bypass in Actualbudget Actual

CVE-2026-42604

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.

Vulnerability class: Broken Access Control

Published · last modified .

EPSS exploit prediction

EPSS: 0.004 (34.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 34.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-42604: held from 0.006 to 0.004.

EPSS over last 30 days · oldest: 0.006 · newest: 0.004 · change: -0.002

Affected products

Weakness classification (CWE)

References