Actual is a local-first personal finance tool. The `POST /openid/config` endpoint in Actual Budget's sync-server…
Summary
Vulnerability reported (CVE-2026-42604). Risk of unauthorized operations or information disclosure. Exploitable via POST /openid/config.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-42604 has been found.
Attackers can target a specific entry point like POST /openid/config over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "CVE-2026-42604" on the vendor's site.
CVE-2026-42604 — CWE-863
Attack surface: POST /openid/config / client_secret
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Incorrect authorization (CWE-863) has been reported. Attackers reach the vulnerable code path via POST /openid/config.
Check the vendor advisory for the affected versions. Attack surface: POST /openid/config / client_secret.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /openid/config requests with malformed payloads or SQL meta-characters. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで影響コンポーネントを特定する。
-
2Hunt for indicators of compromise detect
grep 'POST /openid/config' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /openid/configへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Post-deployment verification verify
Replay attack against POST /openid/config on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- web actualbudget.org