CVE-2026-42604: CWE-863: Incorrect Authorization in actualbudget actual
Actual Budget's sync-server versions up to 26.4.0 have an authorization vulnerability in the POST /openid/config endpoint. This endpoint exposes the full OpenID Connect configuration, including the OAuth2 client_secret, to any caller who knows the bootstrap password. The endpoint lacks authentication and rate limiting, making brute-force attacks on the bootstrap password feasible. Version 26.5.0 addresses this issue.
AI Analysis
Technical Summary
CVE-2026-42604 describes an incorrect authorization vulnerability (CWE-863) in Actual Budget's sync-server versions <= 26.4.0. The POST /openid/config endpoint exposes sensitive OpenID Connect configuration data, including the OAuth2 client_secret, to unauthenticated callers who can provide the bootstrap password. Due to the lack of authentication and rate limiting on this endpoint, the bootstrap password can be brute-forced, potentially allowing unauthorized access to sensitive credentials. The vulnerability is fixed in version 26.5.0.
Potential Impact
Exposure of the OAuth2 client_secret and OpenID Connect configuration to unauthorized parties can lead to compromise of authentication mechanisms and unauthorized access to user data. The lack of authentication and rate limiting increases the risk by enabling brute-force attacks on the bootstrap password. This could undermine the security of the sync-server and potentially user accounts relying on this authentication.
Mitigation Recommendations
Upgrade to Actual Budget sync-server version 26.5.0 or later, where this vulnerability is fixed. Until then, restrict access to the sync-server and monitor for unauthorized access attempts. Patch status is not explicitly confirmed in the vendor advisory, but version 26.5.0 is stated to fix the issue.
CVE-2026-42604: CWE-863: Incorrect Authorization in actualbudget actual
Description
Actual Budget's sync-server versions up to 26.4.0 have an authorization vulnerability in the POST /openid/config endpoint. This endpoint exposes the full OpenID Connect configuration, including the OAuth2 client_secret, to any caller who knows the bootstrap password. The endpoint lacks authentication and rate limiting, making brute-force attacks on the bootstrap password feasible. Version 26.5.0 addresses this issue.
CVSS v4.0
Score 6.9medium
Affected software
pkg:github/actualbudget/actualRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-42604 describes an incorrect authorization vulnerability (CWE-863) in Actual Budget's sync-server versions <= 26.4.0. The POST /openid/config endpoint exposes sensitive OpenID Connect configuration data, including the OAuth2 client_secret, to unauthenticated callers who can provide the bootstrap password. Due to the lack of authentication and rate limiting on this endpoint, the bootstrap password can be brute-forced, potentially allowing unauthorized access to sensitive credentials. The vulnerability is fixed in version 26.5.0.
Potential Impact
Exposure of the OAuth2 client_secret and OpenID Connect configuration to unauthorized parties can lead to compromise of authentication mechanisms and unauthorized access to user data. The lack of authentication and rate limiting increases the risk by enabling brute-force attacks on the bootstrap password. This could undermine the security of the sync-server and potentially user accounts relying on this authentication.
Mitigation Recommendations
Upgrade to Actual Budget sync-server version 26.5.0 or later, where this vulnerability is fixed. Until then, restrict access to the sync-server and monitor for unauthorized access attempts. Patch status is not explicitly confirmed in the vendor advisory, but version 26.5.0 is stated to fix the issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-29T00:31:15.725Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a2c6076e617e2d834b77497
Added to database: 6/12/2026, 7:39:34 PM
Last enriched: 6/12/2026, 7:54:26 PM
Last updated: 6/12/2026, 8:58:20 PM
Views: 4
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.