CVE-2026-27638 PUBLISHED

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

Assigner: GitHub_M
Reserved: 20.02.2026 Published: 26.02.2026 Updated: 26.02.2026

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.

Metrics

CVSS 4.0

CVSS 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
CVSS Score: 5.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	Low
User Interaction	None

CVSS 4.0

Product Status

Vendor	actualbudget
Product	actual
Versions	Version < 26.2.1 is affected

References

Problem Types

CWE-862: Missing Authorization CWE