Admin-triggered service freeze via synchronous regex evaluation
Published Aug 21, 2026 · Updated Aug 21, 2026
Regular expression denial of service in BlueWave Labs Checkmate 3.5.1 through 3.9.1 allows remote authenticated users to freeze the server. AdvancedMatcher constructs a JavaScript RegExp from expectedValue and tests it synchronously against an attacker-controlled HTTP response body without a timeout or worker isolation. An admin or superadmin must enable advanced regex matching on a monitor; catastrophic backtracking then blocks the Node.js event loop, halting API, monitor, and WebSocket processing for all users.
Summary
What happened
Regular expression denial of service in BlueWave Labs Checkmate 3.5.1 through 3.9.1 allows remote authenticated users to freeze the server. AdvancedMatcher constructs a JavaScript RegExp from expectedValue and tests it synchronously against an attacker-controlled HTTP response body without a timeout or worker isolation. An admin or superadmin must enable advanced regex matching on a monitor; catastrophic backtracking then blocks the Node.js event loop, halting API, monitor, and WebSocket processing for all users.
The record
- CVE
- CVE-2026-70656
- Published
- Aug 21, 2026
- Updated
- Aug 21, 2026
- Vendor
- BlueWave Labs
- Product
- Checkmate
- Classifications
- CWE-1333, T1499.004
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- Aug 21, 2026CVE publishedPublication date reported by the CVE source.
- Aug 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.
- Affected versionversion=>= 3.5.1, < 3.9.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- GitHub advisory ReDoS proof of conceptproof of concept · unverified
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Technologies
Your stack
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Your stack
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