CVE-2026-109990
Flying Scripts: Delay JavaScript to Improve Site Speed & Performance <= 1.2.4 - Unauthenticated Stored Cross-Site Scripting via Comment Content
Description
The Flying Scripts: Delay JavaScript to Improve Site Speed & Performance plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'comment' parameter in all versions up to, and including, 1.2.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The exploit bypasses WordPress core's save-time kses sanitization entirely because the payload uses only kses-allowed elements — an <abbr title> attribute and <code> text content — and the XSS is introduced post-save when the plugin's output-buffer rewriter substitutes a double-quote-bearing <code> body into the <abbr title> attribute via predictable, unsalted ___noise___ placeholder keys.
INFO
Published Date :
Oct. 16, 2026, 4:18 a.m.
Last Modified :
Oct. 16, 2026, 4:18 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-109990
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update the Flying Scripts plugin to version 1.2.5 or later.
- Review plugin settings for any suspicious configurations.
- Sanitize and escape all user-provided input.
- Avoid direct use of user input in attributes.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-109990.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-109990 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-109990
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-109990 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-109990 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Oct. 16, 2026
Action Type Old Value New Value Added Description The Flying Scripts: Delay JavaScript to Improve Site Speed & Performance plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'comment' parameter in all versions up to, and including, 1.2.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The exploit bypasses WordPress core's save-time kses sanitization entirely because the payload uses only kses-allowed elements — an <abbr title> attribute and <code> text content — and the XSS is introduced post-save when the plugin's output-buffer rewriter substitutes a double-quote-bearing <code> body into the <abbr title> attribute via predictable, unsalted ___noise___ placeholder keys. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/109xxx/CVE-2026-109990.json">CVE-2026-109990</a> Added Reference https://plugins.trac.wordpress.org/browser/flying-scripts/tags/1.2.4/html-rewrite.php#L36 Added Reference https://plugins.trac.wordpress.org/browser/flying-scripts/tags/1.2.4/html-rewrite.php#L64 Added Reference https://plugins.trac.wordpress.org/browser/flying-scripts/tags/1.2.4/lib/dom-parser.php#L2112 Added Reference https://plugins.trac.wordpress.org/browser/flying-scripts/tags/1.2.4/lib/dom-parser.php#L2207 Added Reference https://plugins.trac.wordpress.org/browser/flying-scripts/tags/1.2.4/lib/dom-parser.php#L2226 Added Reference https://plugins.trac.wordpress.org/browser/flying-scripts/tags/1.2.4/lib/dom-parser.php#L497 Added Reference https://plugins.trac.wordpress.org/changeset?reponame=&old=3737597%40flying-scripts&new=3737597%40flying-scripts Added Reference https://www.wordfence.com/threat-intel/vulnerabilities/id/0ddc518c-02a0-46a5-93e9-0d92a045b35b?source=cve