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CVE-2021-43855

⚠️ high
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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 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 b

Description

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.

CVSS Score
8.2
High
EPSS Score
0.4
Exploit Probability
Published Date
2021-12-27
First Seen: 2026-01-05
📊 Relative Risk Intelligence

This CVE is High Risk - more severe than 79.7% of all 326,604 vulnerabilities in our database.

#66,460
Top 25% most severe
Severity Percentile
Last Modified 2024-11-21
Source NVD 🔗
CVSS Vector 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
CWE IDs (Weakness Types)

📦 Affected Products 1

🔗 References 3

🔗 Related CVEs 6

CVE ID Severity CVSS EPSS Summary Published
CVE-2026-44224 ⚠️ high 8.8 0.1 Wiki.js is an open source wiki app built on Node.js. Prior to 2.5.313, the users.update GraphQL mutation accepts an arbi... 2026-05-12
CVE-2025-56643 ⛔ critical 9.1 0.1 Requarks Wiki.js 2.5.307 does not properly revoke or invalidate active JWT tokens when a user logs out. As a result, pre... 2025-11-18
CVE-2022-1681 ⚠️ high 7.2 0.3 Authentication Bypass Using an Alternate Path or Channel in GitHub repository requarks/wiki prior to 2.5.281. User can g... 2022-05-12
CVE-2022-23654 ⚠️ high 8.1 0.2 Wiki.js is a wiki app built on Node.js. In affected versions an authenticated user with write access on a restricted set... 2022-02-22
CVE-2021-25993 🔶 medium 5.4 0.2 In Requarks wiki.js, versions 2.0.0-beta.147 to 2.5.255 are affected by Stored XSS vulnerability, where a low privileged... 2021-12-29
CVE-2021-43856 ⚠️ high 8.2 0.4 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... 2021-12-27
These CVEs affect the same products