CVE-2026-77616 Semantic MediaWiki affected by reflected XSS in `Special:Ask` via a forged cursor pagination token
Reflected XSS in Semantic MediaWiki allows attackers to execute arbitrary scripts in victims' browsers via a crafted cursor token in Special:Ask.
- 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-2026-77616?
CVE-2026-77616 is a medium-severity cross-site scripting vulnerability in SemanticMediaWiki, published on 18 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
Semantic MediaWiki is a free, open-source extension to MediaWiki that lets users store and query data within the wiki's pages. In versions 7.0.0 through 7.1.0, `Special:Ask` accepts a `cursor` query parameter for keyset pagination (added in 7.0.0). The token is decoded by `CursorEncoder`, which is an **unsigned** base64url-encoded JSON blob, so its contents are fully attacker-controlled. When the cursor's sort anchor does not match the request's `sort=` / `order=`, `QueryCreator::applyCursorIfRequested()` builds an error message by interpolating the attacker-controlled `sort_prop` / `sort_order` values into a raw string via `Query::addErrors()`. Unlike SMW's message-key errors, this raw string bypasses the message layer's sanitization (`ProcessingErrorMsgHandler::normalizeAndDecodeMessages()` passes a non-key, non-encoded string through unchanged). `ErrorWidget::queryError()` then assembles the errors and passes them to `Html::errorBox()`, whose first argument is emitted as raw HTML. The result is a reflected cross-site scripting vulnerability: a crafted `cursor` token containing markup in `sort_prop` (or `sort_order`) executes script in the victim's browser on the wiki origin. No authentication or special permission is required. The payload is delivered via a crafted link. Version 7.2.0 contains a fix.
Weakness: CWE-79
Which versions are affected by CVE-2026-77616?
2 open source packages ship an affected version, including mediawiki/semantic-media-wiki.
| Package | Affected | Fixed in |
|---|---|---|
mediawiki/semantic-media-wiki Packagist | From 7.0.0 | 7.2.0 |
mediawiki/semantic-media-wiki Packagist | From 7.0.0 | 7.2.0 |
How do I fix CVE-2026-77616?
Upgrade mediawiki/semantic-media-wiki to 7.2.0 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-2026-77616 being exploited?
There is no known exploitation of CVE-2026-77616 in the wild and no public exploit code.
Sources
Also known as GHSA-cx86-7xwp-w9wf.