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The vulnerability known as a Regular Expression Denial of Service (ReDoS) occurs within the content import functionality of the Ghost content management system. When Ghost processes an improperly formatted or maliciously crafted import file, it evaluates complex regular expressions against specific strings. Certain input patterns trigger catastrophic backtracking within the underlying Node.js regular expression engine, consuming excessive CPU cycles. Because JavaScript operates on a single-threaded event loop, this intensive computational load completely blocks execution threads, rendering the Ghost server entirely unresponsive to legitimate user requests. Although exploitation requires administrative privileges to perform content imports, a successful attack compromises instance availability, causing severe operational disruptions for self-hosted and managed deployments alike.
DailyCVE Form:
Platform: Ghost CMS
Version: v4.0.0-v6.65.0
Vulnerability : ReDoS
Severity : Moderate
date: Oct 1, 2026
Prediction: October 2026
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Bash commands and codes related to the blog
Check current installed Ghost version via Ghost-CLI ghost version Update Ghost instance to version 6.67.0 containing the security patch ghost update 6.67.0 For Docker-based deployments, pull the updated image tag docker pull ghost:latest docker compose up -d --force-recreate
Exploit: (Educational Purposes!)
// Conceptual demonstration of ReDoS input triggering catastrophic backtracking
const maliciousInput = "A".repeat(10000) + "!";
const vulnerableRegex = /^(a+)+$/;
console.time("Execution Time");
vulnerableRegex.test(maliciousInput); // Blocks event loop
console.timeEnd("Execution Time");
Protection: from this CVE
To protect your Ghost installation against this vulnerability, immediately upgrade your platform to version 6.67.0 or later where proper input sanitization and regex bounding are enforced. Restrict administrative panel access strictly to trusted personnel to mitigate the risk of privileged exploitation.
Impact:
A successful exploitation of this flaw leads to a total denial of service by spiking CPU usage to maximum capacity, rendering the application server completely unresponsive and disrupting all hosted publishing operations.
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Sources:
Reported By: github.com
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