Executive brief
YesWiki, a collaborative wiki platform, is vulnerable to a security flaw where malicious code can be injected into the page history view. An attacker can send a specially crafted link to a user; if clicked, the attacker can execute arbitrary commands in the user's browser, potentially leading to data theft or unauthorized actions. This risk is particularly high on sites where anonymous editing is enabled, as it can target any visitor.
Technical details
A reflected cross-site scripting (XSS) vulnerability exists in YesWiki's `handlers/page/show.php` component. The application fails to sanitize the `time` GET parameter before reflecting it into a hidden HTML input field within the archived-revision edit form. While the parameter is used in a SQL query, MySQL's type coercion allows malformed DATETIME strings (containing XSS payloads) to successfully match valid revision timestamps. An attacker can exploit this by crafting a URL that includes a valid timestamp followed by a JavaScript payload. Execution requires the victim to have read and write access to the target page, though this is often available to anonymous users in default configurations. The issue is fixed in version 4.6.6.
Affected products
- YesWiki YesWiki >= 4.1.0, < 4.6.6
Timeline
- 2026-06-02: disclosed
- 2026-06-02: patched: Commit 35ad9c2bb6cd338198b37c1f745e24bc302a3560
- 2026-07-09: advisory