CVE-2026-58270: CWE-1333: Inefficient Regular Expression Complexity in Sync-in server
Sync-in Server versions prior to 2.4.0 contain a vulnerability in the sync diff endpoint where user-supplied strings are compiled into regular expressions without complexity validation. This can lead to catastrophic backtracking patterns that block the Node.js event loop, rendering the server unresponsive until restarted. The issue is patched in version 2.4.0.
AI Analysis
Technical Summary
The Sync-in Server before version 2.4.0 allows user input to be compiled into a regular expression without checking for complexity. Specifically, patterns like '^(a+)+b' can cause catastrophic backtracking, which blocks the Node.js event loop and causes a denial of service by making the server unresponsive. This vulnerability is addressed in version 2.4.0, which includes a fix to prevent such inefficient regular expression complexity.
Potential Impact
Exploitation of this vulnerability results in a denial of service condition where the Node.js event loop is blocked, making the entire Sync-in Server unresponsive to all users until the container is restarted. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Upgrade Sync-in Server to version 2.4.0 or later, where the vulnerability is patched. No other mitigations are indicated or required.
CVE-2026-58270: CWE-1333: Inefficient Regular Expression Complexity in Sync-in server
Description
Sync-in Server versions prior to 2.4.0 contain a vulnerability in the sync diff endpoint where user-supplied strings are compiled into regular expressions without complexity validation. This can lead to catastrophic backtracking patterns that block the Node.js event loop, rendering the server unresponsive until restarted. The issue is patched in version 2.4.0.
CVSS v3.1
Score 6.5medium
Affected software
Sync-in
server
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Sync-in Server before version 2.4.0 allows user input to be compiled into a regular expression without checking for complexity. Specifically, patterns like '^(a+)+b' can cause catastrophic backtracking, which blocks the Node.js event loop and causes a denial of service by making the server unresponsive. This vulnerability is addressed in version 2.4.0, which includes a fix to prevent such inefficient regular expression complexity.
Potential Impact
Exploitation of this vulnerability results in a denial of service condition where the Node.js event loop is blocked, making the entire Sync-in Server unresponsive to all users until the container is restarted. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Upgrade Sync-in Server to version 2.4.0 or later, where the vulnerability is patched. No other mitigations are indicated or required.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-29T21:54:30.332Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ab1abbc55bf5e2cf58b4685
Added to database: 09/21/2026, 22:12:12 UTC
Last enriched: 09/21/2026, 22:14:27 UTC
Last updated: 09/22/2026, 00:41:40 UTC
Views: 5
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