# 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.

- **Severity:** Medium 6.9 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Jun 2026
- **Updated:** 15 Jun 2026
- **Also known as:** GHSA-49v6-pqjq-xw55

## 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 (Incorrect Authorization)

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42604 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-42604 in the wild and no public exploit code.

Affected product: actualbudget actual. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42604/ (Markdown: https://insights.sbomify.com/CVE-2026-42604/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42604
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42604
- OSV: https://osv.dev/vulnerability/CVE-2026-42604

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42604/
Summaries are generated and may contain mistakes; the official description above is the record.