---
id: CVE-2026-58270
title: >-
  Sync-in Server is an open-source platform for file storage, sharing,
  collaboration, and syncing
summary: >-
  Sync-in Server is an open-source platform for file storage, sharing,
  collaboration, and syncing. Prior to version 2.4.0, the sync diff endpoint
  compiles a user-supplied string into a `RegExp` with no complexity validation.
  A catastrophic…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-1333
vendor: Sync-in
product: server
affected:
  - server < 2.4.0
patched:
  - '@sync-in/server 2.4.0'
published: '2026-09-21'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T21:25:27.050'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-58270'
references:
  - url: 'https://github.com/Sync-in/server/security/advisories/GHSA-jx63-h26r-8cph'
    label: security-advisories@github.com
  - url: 'https://github.com/Sync-in/server/security/advisories/GHSA-jx63-h26r-8cph'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-58270'
  - url: 'https://github.com/Sync-in/server/pull/228'
  - url: >-
      https://github.com/Sync-in/server/commit/b1dcaa1d1c1bb17ab6c31a404cc9cead7efdd979
  - url: 'https://github.com/Sync-in/server/releases/tag/v2.4.0'
  - url: 'https://github.com/advisories/GHSA-jx63-h26r-8cph'
tags:
  - nvd
  - cve.org
  - ghsa
  - npm
  - exploit-available
epss: 0.00348
epssPercentile: 0.25597
aliases:
  - GHSA-jx63-h26r-8cph
ecosystem: npm
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-22T14:06:26.710916Z'
ingestedAt: '2026-09-21T20:52:58.298Z'
---

## Overview

Sync-in Server is an open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.4.0, the sync diff endpoint compiles a user-supplied string into a `RegExp` with no complexity validation. A catastrophic-backtracking pattern (e.g. `^(a+)+b`) blocks the Node.js event loop, making the entire server unresponsive to all users until the container is restarted. Version 2.4.0 patches the issue.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-58270)

Affected packages:

- `@sync-in/server <= 2.3.0`

Patched in:

- `@sync-in/server 2.4.0`

Source: https://github.com/advisories/GHSA-jx63-h26r-8cph