CVE-2026-111442: XSS
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Backdrop CMS Coreto a version that resolves this vulnerability.Fixed in 1.35.2 - Upgrade
Upgrade
Backdrop CMS Coreto a version that resolves this vulnerability.Fixed in 1.34.6
Event History
Frequently Asked Questions
Who can exploit this issue?
An attacker must have permission to upload SVG images. Exploitation also requires someone to open the uploaded SVG directly at its URL.
Are sites that display uploaded SVGs through normal Backdrop pages exposed to script execution?
Backdrop embeds uploaded SVG images using <img> tags, which prevents embedded SVG scripts from executing. The embedded scripting runs only when the SVG is viewed directly by URL.
Which releases need to be updated?
Affected releases are Backdrop CMS Core 1.35.x before 1.35.2 and 1.34.x before 1.34.6.