CVE-2026-42604 Actual has an OpenID `client_secret` Disclosure via Broken Authorization Guard in `/openid/config`
Attackers can retrieve OpenID client secrets and brute-force bootstrap passwords due to missing authentication on the config endpoint.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-42604?
CVE-2026-42604 is a medium-severity vulnerability in actualbudget actual, published on 12 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-863
Which versions are affected by CVE-2026-42604?
How do I fix CVE-2026-42604?
No fix has been published for CVE-2026-42604 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-42604 being exploited?
There is no known exploitation of CVE-2026-42604 in the wild and no public exploit code.
Sources
Also known as GHSA-49v6-pqjq-xw55.