CVE-2026-8623: XSS (CVSS 6.4)

Description

The Dear Flipbook – PDF Flipbook, 3D Flipbook, PDF embed, PDF viewer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'post_content (class attribute of .dvcss element)' parameter in all versions up to, and including, 2.4.30 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload is embedded as a Base64-encoded JSON object in a CSS class name on a Custom HTML block; the frontend parseCSSElements() function decodes it client-side with atob() and JSON.parse() and renders the logo property as raw HTML, meaning no server-side or client-side sanitization intercepts the malicious script before DOM insertion.

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CVSS v3.1 Score

6.4

MEDIUM

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

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.12%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://plugins.trac.wordpress.org/browser/3d-flipbook-dflip-lite/tags/2.4.27/assets/js/dflip.js#L11255 https://plugins.trac.wordpress.org/browser/3d-flipbook-dflip-lite/tags/2.4.27/assets/js/dflip.js#L2687 https://plugins.trac.wordpress.org/changeset/3641463/3d-flipbook-dflip-lite/trunk/assets/js/dflip.js https://plugins.trac.wordpress.org/changeset?old_path=%2F3d-flipbook-dflip-lite/tags/2.4.30&new_path=%2F3d-flipbook-dflip-lite/tags/2.4.37 https://plugins.trac.wordpress.org/changeset?reponame=&new=3641463%403d-flipbook-dflip-lite%2Ftags%2F2.4.37&old=3557511%403d-flipbook-dflip-lite%2Ftags%2F2.4.30 https://www.wordfence.com/threat-intel/vulnerabilities/id/27e2848d-6271-4bb9-92e2-0f8c8860745d?source=cve

Frequently Asked Questions

What is CVE-2026-8623? +

The Dear Flipbook – PDF Flipbook, 3D Flipbook, PDF embed, PDF viewer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'post_content (class attribute of .dvcss element)' parameter in all versions up to, and including, 2.4.30 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload is embedded as a Base64-encoded JSON object in a CSS class name on a Custom HTML block; the frontend parseCSSElements() function decodes it client-side with atob() and JSON.parse() and renders the logo property as raw HTML, meaning no server-side or client-side sanitization intercepts the malicious script before DOM insertion. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2026-8623? +

CVE-2026-8623 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-8623? +

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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