CVE-2026-73628 Serendipity 2.3.5 Reflected XSS via search clean-URL route
Attackers can execute arbitrary JavaScript in victims' browsers via crafted search links due to improper sanitization order in Serendipity.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-73628?
CVE-2026-73628 is a medium-severity cross-site scripting vulnerability in s9y Serendipity, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Serendipity versions >= 2.3.5 and <= 2.6.0 contain a reflected cross-site scripting vulnerability in the search clean-URL route (/search/<term>). In include/functions_routing.inc.php serveSearch(), the sanitisation pipeline runs urldecode() after HTML-encoding, so a single URL-encoded HTML payload survives strip_tags() and htmlspecialchars() and is then decoded back into live HTML in the page. A crafted search link can execute arbitrary JavaScript in the victim's browser. Fixed in 2.6.1.
Weakness: CWE-79
Which versions are affected by CVE-2026-73628?
How do I fix CVE-2026-73628?
No fix has been published for CVE-2026-73628 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-2026-73628 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73628 exists.
Sources
Also known as GHSA-4g8w-wg6x-gvqc, GHSA-6c2x-mjmq-vx4q.