CVE-2026-58270Public exploitNetwork attack vector

Authenticated service hang via unsafe sync regex

Published Sep 21, 2026 · Updated Sep 21, 2026

ReDoS in Sync-in Server before 2.4.0 allows remote authenticated users to interrupt service through a crafted sync path filter. SyncDiffDto compiles pathFilters directly as a RegExp, and synchronous test() calls can catastrophically backtrack on relative file paths. A non-guest account with desktop sync access, a registered client, and a matching worst-case path are required; the event loop and all HTTP requests then hang.

CVSS severity6.5
Medium
EPSS probability0.35%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

ReDoS in Sync-in Server before 2.4.0 allows remote authenticated users to interrupt service through a crafted sync path filter. SyncDiffDto compiles pathFilters directly as a RegExp, and synchronous test() calls can catastrophically backtrack on relative file paths. A non-guest account with desktop sync access, a registered client, and a matching worst-case path are required; the event loop and all HTTP requests then hang.

The record

CVE
CVE-2026-58270
Published
Sep 21, 2026
Updated
Sep 21, 2026
Vendor
Sync-in
Product
Sync-in Server
Classifications
CWE-1333, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Sync-in · Sync-in Serverversion=< 2.4.0

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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