CVE-2026-27638
Received Received - Intake
Insecure Access Control in Actual Sync API Allows Data Manipulation

Publication date: 2026-02-26

Last updated on: 2026-02-27

Assigner: GitHub, Inc.

Description
Actual is a local-first personal finance tool. Prior to version 26.2.1, in multi-user mode (OpenID), the sync API endpoints (`/sync/*`) don't verify that the authenticated user owns or has access to the file being operated on. Any authenticated user can read, modify, and overwrite any other user's budget files by providing their file ID. Version 26.2.1 patches the issue.
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Meta Information
Published
2026-02-26
Last Modified
2026-02-27
Generated
2026-06-16
AI Q&A
2026-02-27
EPSS Evaluated
2026-06-15
NVD
CVE-2026-27638
EUVD
EUVD-2026-8905
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
actualbudget actual to 26.2.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-862 The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
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Executive Summary

This vulnerability affects the Actual personal finance tool in its multi-user mode using OpenID. Before version 26.2.1, the sync API endpoints (those under `/sync/*`) did not verify whether the authenticated user actually owned or had access to the budget file they were trying to operate on.

As a result, any authenticated user could read, modify, or overwrite any other user's budget files simply by providing the file ID, without proper authorization checks.

This issue was fixed in version 26.2.1.

Impact Analysis

This vulnerability can lead to unauthorized access and modification of personal financial data stored in the Actual application.

An attacker who is authenticated can read sensitive budget files of other users, potentially exposing private financial information.

Additionally, the attacker can modify or overwrite other users' budget files, leading to data loss, corruption, or manipulation.

Compliance Impact

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Detection Guidance

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Mitigation Strategies

To mitigate this vulnerability, upgrade the Actual personal finance tool to version 26.2.1 or later, which patches the issue.

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