CVE-2021-43855

Stored XSS via SVG in Requarks/wiki

MEDIUM
5.4
CVSS Score
Published: December 27, 2021 at 06:05 PM UTC
Updated: June 17, 2026 at 04:11 AM UTC
1 product affected across 1 vendorWiki.js

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.9%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.5.264
Affected range stops below 2.5.264, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-79

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