CVE-2026-3089: @actual app/sync server Path Traversal Vulnerability

MODERATE
Advisory Identifier: GHSA-27vg-33gh-4hwg
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CWE-22
Published
Advisory Summary

CVE-2026-3089 is a MODERATE path traversal vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting @actual app/sync server libraries in the npm ecosystem. The issue involves actual sync server has an authenticated path traversal. Remediation is available by upgrading affected packages to version 26.3.0.

CVE-2026-3089 at a Glance

CVE Identifier CVE-2026-3089
GHSA Identifier GHSA-27vg-33gh-4hwg
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product @actual app/sync server
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-3089

To remediate this vulnerability, upgrade all affected @actual app/sync server dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@actual-app/sync-server fixed: 26.3.0 
npm install @actual-app/sync-server@26.3.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @actual-app/sync-server

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-3089, inspect your project dependencies using npm:

npm ls @actual-app/sync-server

Analyze the terminal output to locate any version of @actual app/sync server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 26.3.0), your application is affected.

Note: The npm ls @actual-app/sync-server command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In @actual app/sync server, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

# 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`. ## Mitigations The vulnerability can be mitigated in prior versions by running the sync server in a filesystem sandbox.

CVE-2026-3089 Affected @actual app/sync server Versions

1 component(s)
Fixed Versions:
26.3.0
Product / Package Ecosystem Affected Versions Fixed Version
@actual-app/sync-server
npm/@actual-app/sync-server
npm
< 26.3.0
26.3.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/actualbudget/actual/security/advisories/GHSA-27vg-33gh-4hwg
NVD — CVE-2026-3089 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3089
@actual app/sync server Source Repository REPOSITORY
https://github.com/actualbudget/actual/pull/7067
Security Fix Commit FIX COMMIT
https://github.com/actualbudget/actual/commit/18072e1d8b5281db43ded8b21433ee177bae9dfa
fluidattacks.com/advisories/fugue WEB
https://fluidattacks.com/advisories/fugue
@actual app/sync server Source Repository REPOSITORY
https://github.com/actualbudget/actual

Frequently Asked Questions

What is CVE-2026-3089?
CVE-2026-3089 is a security vulnerability in @actual app/sync server involving Actual Sync Server has an Authenticated Path Traversal under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which @actual app/sync server versions are affected?
Affected versions include releases prior to 26.3.0 across affected packages: @actual-app/sync-server.
What version fixes CVE-2026-3089?
Upgrading to 26.3.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @actual-app/sync-server affected?
Yes, @actual-app/sync-server is affected in releases prior to 26.3.0. Upgrade your dependency to 26.3.0 or later.
What CWE is associated with CVE-2026-3089?
CVE-2026-3089 is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check npm dependencies for CVE-2026-3089?
Run the dependency tree command: 'npm ls @actual-app/sync-server'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-27vg-33gh-4hwg",
  "modified" : "2026-03-10T01:02:15Z",
  "published" : "2026-03-10T01:02:15Z",
  "aliases" : [ "CVE-2026-3089" ],
  "summary" : "Actual Sync Server has an Authenticated Path Traversal",
  "details" : "# Description\n\nActual 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`.\n\n## Mitigations\nThe vulnerability can be mitigated in prior versions by running the sync server in a filesystem sandbox.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@actual-app/sync-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "26.3.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 26.2.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/actualbudget/actual/security/advisories/GHSA-27vg-33gh-4hwg"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-3089"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/actualbudget/actual/pull/7067"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/actualbudget/actual/commit/18072e1d8b5281db43ded8b21433ee177bae9dfa"
  }, {
    "type" : "WEB",
    "url" : "https://fluidattacks.com/advisories/fugue"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/actualbudget/actual"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-10T01:02:15Z",
    "nvd_published_at" : "2026-03-09T14:16:10Z"
  }
}