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CVE-2021-43855: Wiki.js is a wiki app built on node.js. Wiki.js 2.5.263 and earlier is vulnerable to stored cross-site scripting through a SVG file upload made via a custom request with a fake MIME type. By creati...
CVE-2021-43855 · published 4 years ago
Summary
Wiki.js is a wiki app built on node.js. Wiki.js 2.5.263 and earlier is vulnerable to stored cross-site scripting through a SVG file upload made via a custom request with a fake MIME type. By creating a crafted SVG file, a malicious Wiki.js user may stage a stored cross-site scripting attack. This al...
What to do
- Update requarks wiki.js to version 2.5.264 or later.
Affected software
| Vendor | Product | Affected versions |
|---|---|---|
| requarks | wiki.js |
< 2.5.264 cpe:2.3:a:requarks:wiki.js:*:*:*:*:*:*:*:* |
Original advisory text
Wiki.js is a wiki app built on node.js. Wiki.js 2.5.263 and earlier is vulnerable to stored cross-site scripting through a SVG file upload made via a custom request with a fake MIME type. By creati...
Wiki.js is a wiki app built on node.js. Wiki.js 2.5.263 and earlier is vulnerable to stored cross-site scripting through a SVG file upload made via a custom request with a fake MIME type. By creating a crafted SVG file, a malicious Wiki.js user may stage a stored cross-site scripting attack. This allows the attacker to execute malicious JavaScript when the SVG is viewed directly by other users. Scripts do not execute when loaded inside a page via normal `<img>` tags. The malicious SVG can only be uploaded by crafting a custom request to the server with a fake MIME type. A patch in version 2.5.264 fixes this vulnerability by adding an additional file extension verification check to the optional (enabled by default) SVG sanitization step to all file uploads that match the SVG mime type. As a workaround, disable file upload for all non-trusted users.
References
- https://github.com/Requarks/wiki/commit/57b56d3a5b9c00358814e76f3ee5b4bb353ad62f Patch Third Party Advisory
- https://github.com/Requarks/wiki/releases/tag/2.5.264 Release Notes Third Party Advisory
- https://github.com/Requarks/wiki/security/advisories/GHSA-4893-pj5w-3hq9 Exploit Patch Third Party Advisory
Internet-facing
60 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit (estimated)
- Gives an attacker partial control (estimated)
Type
CWE-79Cross-site Scripting (XSS)
Timeline
Published27 Dec 2021
Updated3 Nov 2026
First seen29 Sep 2026
Sources
CVE-2021-43855 · NVD
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