Vulnerability · Published Feb 26, 2026 · Assigned by GitHub_M

CVE-2026-27638ActualBudget missing authorization in sync endpoints allows cross-user budget file access in multi-user mode

Medium 5.7

In plain English

A medium-severity missing authorization in actual from actualbudget. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.7Medium
Exploit odds (30 days)0.3%top 72.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
npm@actual-app/sync-server26.2.1GHSA-qmjj-p7m9-wjrv

Affected products (as reported)

VendorProductVersions
actualbudget actual < 26.2.1

Weakness: CWE-862 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

References