PT-2021-23981 · Wiki.Js · Wiki.Js

Haxatron · Published 2021-12-27 · Updated 2022-01-07 · CVE-2021-43855

Positive Technologies (AI Summary)

CVSS v3.1

8.2

High

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

Name of the Vulnerable Software and Affected Versions: Wiki.js versions 2.5.263 and earlier

Description: The issue concerns 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, allowing 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.

Recommendations: For Wiki.js versions 2.5.263 and earlier, update to version 2.5.264, which adds an additional file extension verification check to the optional SVG sanitization step to all file uploads that match the SVG mime type. As a temporary workaround, consider disabling file upload for all non-trusted users.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2021-43855

GHSA-4893-PJ5W-3HQ9

Affected Products

Wiki.Js

References · 6

• 🔥 https://github.com/Requarks/wiki/security/advisories/GHSA-4893-pj5w-3hq9 · Exploit
• https://github.com/Requarks/wiki/commit/57b56d3a5b9c00358814e76f3ee5b4bb353ad62f · Patch
• https://osv.dev/vulnerability/CVE-2021-43855 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-43855 · Security Note
• https://github.com/Requarks/wiki/releases/tag/2.5.264 · Note
• https://t.me/cibsecurity/34679 · Telegram Post