CVE-2026-52774 Reflected XSS via Unescaped `id` Parameter in Bazar Widget HTML Attributes in YesWiki
Attackers can execute arbitrary JavaScript in victims' browsers via reflected XSS in the Bazar widget, requiring the extension to be enabled.
- 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
- Available
What is CVE-2026-52774?
CVE-2026-52774 is a medium-severity cross-site scripting vulnerability in yeswiki, published on 4 Sep 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
YesWiki is a wiki system written in PHP. Prior to version 4.6.6, YesWiki's Bazar widget handler reflects the id GET parameter into HTML attributes using strip_tags() only. Because strip_tags() does not escape double quotes, an attacker can break out of the attribute value, inject an event handler such as onmouseover, and execute arbitrary JavaScript in the victim's browser. This issue is reachable without authentication. During validation, the vulnerable widget route returned the injected HTML for both /HomePage/widget?id=... and /NoSuchPage/widget?id=..., which shows that no login, no page ownership, no edit rights, and not even a valid page tag were required. The only routing prerequisite observed was that the Bazar extension is enabled and the request includes an id parameter. This issue has been patched in version 4.6.6.
Weakness: CWE-80
Which versions are affected by CVE-2026-52774?
2 open source packages ship an affected version, including yeswiki/yeswiki.
| Package | Affected | Fixed in |
|---|---|---|
yeswiki/yeswiki Packagist | All versions | 4.6.6 |
yeswiki/yeswiki Packagist | All versions | 4.6.6 |
How do I fix CVE-2026-52774?
Upgrade yeswiki/yeswiki to 4.6.6 or later.
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-2026-52774 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52774 exists.
Public exploit code: 1 Nuclei template and 1 proofs of concept on GitHub.
Sources
Also known as GHSA-r5xw-gcgw-hwp5.