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CVE-2021-43856

⚠️ 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 non-image file uploads for file types that can be viewed directly inline in the browser. By creating a malicious file which can execute inline JS when viewed in the browser (e.g. XML files), a malicious Wiki.js user may stage a stored cross-site scripting attack. This allows the attacker to execute malicious JavaScript when the file is viewed directly by other users. The file

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 non-image file uploads for file types that can be viewed directly inline in the browser. By creating a malicious file which can execute inline JS when viewed in the browser (e.g. XML files), a malicious Wiki.js user may stage a stored cross-site scripting attack. This allows the attacker to execute malicious JavaScript when the file is viewed directly by other users. The file must be opened directly by the user and will not trigger directly in a normal Wiki.js page. A patch in version 2.5.264 fixes this vulnerability by adding an optional (enabled by default) force download flag to all non-image file types, preventing the file from being viewed inline in the browser. As a workaround, disable file upload for all non-trusted users. --- Thanks to @Haxatron for reporting this vulnerability. Initially reported via https://huntr.dev/bounties/266bff09-00d9-43ca-a4bb-bb540642811f/

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-2021-43855 ⚠️ 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