CVE-2026-77616: Semantic MediaWiki reflected XSS in Special:Ask cursor parameter

CVE-2026-77616 · Severity: medium · CVSS 6.1 · Published 2026-09-18

Semantic MediaWiki's Special:Ask search interface accepts user-supplied pagination tokens that are not properly validated or encoded before display. An attacker can craft a malicious link containing JavaScript code in the pagination token, which executes in a victim's browser when the page loads, potentially stealing credentials or wiki data. No authentication is required; the attack is delivered via a simple phishing link.

Technologies: mediawiki/semantic-media-wiki (Packagist), Semantic MediaWiki. Vendors: Packagist, Semantic MediaWiki.

Quick answers

Is CVE-2026-77616 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-77616 being exploited in the wild.
How severe is CVE-2026-77616?
Medium severity, with a CVSS score of 6.1, published 18 September 2026.
Which products and versions are affected?
mediawiki/semantic-media-wiki (Packagist) >= 7.0.0, <= 7.1.0, ECOSYSTEM:introduced=7.0.0,fixed=7.2.0; Semantic MediaWiki 7.0.0 and later.
Is there a fix for CVE-2026-77616?
Yes. mediawiki/semantic-media-wiki (Packagist): upgrade to 7.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-77616 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-77616?
Check whether you run mediawiki/semantic-media-wiki (Packagist) or Semantic MediaWiki at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • mediawiki/semantic-media-wiki (Packagist): upgrade to 7.2.0 or later
    composer require mediawiki/semantic-media-wiki:^7.2.0

Technical details

The vulnerability is a reflected cross-site scripting (XSS) flaw in the Special:Ask page's cursor-based pagination mechanism. The `cursor` query parameter is a base64url-encoded JSON blob that is decoded without signature verification, allowing an attacker to forge arbitrary content. When the cursor's sort parameters do not match the request sort parameters, the code builds an error message by directly interpolating the attacker-controlled `sort_prop` and `sort_order` fields into a raw string via `Query::addErrors()`, bypassing the normal message sanitization layer. This unsanitized error text is then passed to `Html::errorBox()` which emits it as raw HTML without output encoding. The attack requires only network access and a crafted URL; the victim must click the link. The fix involves output-encoding the `sort_prop` and `sort_order` values before interpolation into error messages.

Affected products

  • Semantic MediaWiki Semantic MediaWiki 7.0.0 and later

Identifiers

  • CVE-2026-77616
  • GHSA-cx86-7xwp-w9wf

Timeline

  • 2026-09-18: disclosed
  • 2026-09-18: advisory: GHSA-cx86-7xwp-w9wf

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