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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-02-26

Last Modified

2026-02-27

Generated

2026-07-06

AI Q&A

2026-02-27

EPSS Evaluated

2026-07-05

NVD

CVE-2026-27638

EUVD

EUVD-2026-8905

Affected Vendors & Products

Vendor	Product	Version / Range
actualbudget	actual	to 26.2.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

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.

Attack-Flow Graph

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

I don't know

Detection Guidance

I don't know

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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