CVE intelligence and bounded remediation

CVE-2025-25063 — An XSS issue was discovered in Backdrop CMS 1.28.x before 1.28.5 and 1.29.x before 1.29.3

Medium CVSS 4.4

An XSS issue was discovered in Backdrop CMS 1.28.x before 1.28.5 and 1.29.x before 1.29.3. It does not sufficiently validate uploaded SVG images to ensure they do not contain potentially dangerous SVG tags. SVG images can contain clickable links and executable scripting, and using 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 scripting from executing. The SVG must be viewed directly by its URL in order to run any embedded scripting.

Severity
Medium
CVSS
4.4 (3.1)
Published
2025-02-03
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-79

Affected products

  • backdropcms / backdrop_cms

Showing 1 representative product identities from 2 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Cross-site scripting and unsafe browser output

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Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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