CVE-2026-111442
Received Received - Intake

Stored XSS via Malicious SVG Upload in Backdrop CMS

Publication date: 2026-10-16

Last updated on: 2026-10-16

Assigner: MITRE

Description
Backdrop CMS Core 1.35.x before 1.35.2 and 1.34.x before 1.34.6 does not sufficiently validate uploaded SVG images to ensure they lack potentially dangerous SVG tags. SVG images can contain clickable links or executable scripting. By uploading a crafted SVG, it is possible to execute scripting in the browser when an SVG image is viewed. This issue is mitigated by the attacker needing to be able to upload SVG images, and that Backdrop embeds all uploaded SVG images within <img> tags, which prevents script from executing. The SVG must be viewed directly by its URL in order to run any embedded scripting.

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Meta Information

Published
2026-10-16
Last Modified
2026-10-16
Generated
2026-10-16
AI Q&A
2026-10-16
EPSS Evaluated
N/A
NVD
CVE-2026-111442
EUVD
EUVD-2026-102595

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
BackdropCMS Backdrop 1.35.0
BackdropCMS Backdrop 1.34.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This vulnerability is a cross-site scripting (XSS) issue in Backdrop CMS Core versions before 1.35.2 and 1.34.6. It occurs because SVG images are not properly validated during upload, allowing malicious scripts or clickable links to be embedded. While Backdrop CMS mitigates this by embedding SVGs in img tags, direct access to the SVG file URL could still execute embedded scripting in the browser.

Detection Guidance

Check Backdrop CMS version using commands like 'drush core-status' or 'composer show backdrop/core'. Inspect uploaded SVG files for suspicious tags or scripts. Monitor browser console logs when viewing SVG files directly via URL.

Impact Analysis

An attacker could upload a crafted SVG file to exploit this vulnerability. If a user views the SVG directly via its URL, embedded scripting may execute in their browser. This could lead to unauthorized actions, data theft, or other malicious activities depending on user privileges.

Mitigation Strategies

Update Backdrop CMS to version 1.35.2 or 1.34.6 immediately. Disable SVG uploads if not required. Restrict file upload permissions to trusted users only. Review and remove any suspicious SVG files already uploaded.

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