CVE-2021-43800: Wiki.js is a wiki app built on Node.js. (CVSS 7.5)

Wiki.js is a wiki app built on Node.js.

Wiki.js is a wiki app built on Node.js. Prior to version 2.5.254, directory traversal outside of Wiki.js context is possible when a storage module with local asset cache fetching is enabled on a Windows host. A malicious user can potentially read any file on the file system by crafting a special URL that allows for directory traversal. This is only possible on a Wiki.js server running on Windows, when a storage module implementing local asset cache (e.g Local File System or Git) is enabled and that no web application firewall solution (e.g. cloudflare) strips potentially malicious URLs. Commit number 414033de9dff66a327e3f3243234852f468a9d85 fixes this vulnerability by sanitizing the path before it is passed on to the storage module. The sanitization step removes any windows directory traversal sequences from the path. As a workaround, disable any storage module with local asset caching capabilities (Local File System, Git).

Description from the National Vulnerability Database, published by GitHub

What it means for a small business

If your business uses wiki, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 1.8%, higher than 78% of CVEs. That’s above average: worth scheduling this week. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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