CVE-2025-25062: backdrop cms XSS — Exploit & Fix

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.

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CVSS v3.1 Score

4.4

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
backdropcms	backdrop_cms	1.28.0 — 1.28.5
backdropcms	backdrop_cms	1.29.0 — 1.29.3

References

Advisories & Patches

https://backdropcms.org/security/backdrop-sa-core-2025-001

Exploits

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/

Frequently Asked Questions

What is 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. 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. It has a CVSS v3.1 base score of 4.4 (MEDIUM).

How severe is CVE-2025-25062? +

CVE-2025-25062 has a CVSS v3.1 score of 4.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-25062? +

CVE-2025-25062 affects products from backdropcms, specifically: backdrop_cms. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-25062? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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