CVE-2026-3089: Actual Sync Server 26.2.1 - Authenticated Path Traversal

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-03-09 · updated 2026-06-17
Weakness: CWE-22

Description

Actual Sync Server allows authenticated users to upload files through POST /sync/upload-user-file. In versions prior to 26.3.0, improper validation of the user-controlled x-actual-file-id header means that traversal segments (../) can escape the intended directory and write files outside userFiles.This issue affects prior versions of Actual Sync Server 26.3.0.

Affected products

actualbudget actual: before 26.3.0 — fixed in 26.3.0

How to fix

Upgrade to a fixed version: actualbudget actual 26.3.0. Check the vendor advisory for mitigations.

References

https://fluidattacks.com/advisories/fugue
https://github.com/actualbudget/actual
https://github.com/actualbudget/actual/pull/7067
https://fluidattacks.com/advisories/fugue

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