CVE-2026-109990 Cross-site scripting in Flying Scripts: Delay JavaScript to Improve Site Speed & Performance
Unauthenticated attackers can inject arbitrary web scripts via comment content, leading to stored XSS execution when users view affected pages.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-109990?
CVE-2026-109990 is a high-severity cross-site scripting vulnerability in gijo Flying Scripts: Delay JavaScript to Improve Site Speed & Performance, published on 16 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2026-109990?
How do I fix CVE-2026-109990?
No fix has been published for CVE-2026-109990 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-109990 being exploited?
There is no known exploitation of CVE-2026-109990 in the wild and no public exploit code.
Sources
Also known as GHSA-x96v-mfm7-f4rv.