CVE-2026-52774: YesWiki is a wiki system written in PHP. (CVSS 6.1)

YesWiki is a wiki system written in PHP.

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.

Description from the National Vulnerability Database, published by GitHub

What it means for a small business

If your business uses yeswiki, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.66%, higher than 51% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 28, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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