Summary
Semantic MediaWiki affected by reflected XSS in Special:Ask via a forged cursor pagination token
Reflected XSS via a forged cursor pagination token
Failure mode
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 sanitisation (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, e.g. Special:Ask?q=...&p[cursor]=<forged token> where the token decodes to {"v":1,"sort_prop":"<script>...</script>"}. Confirmed executing in a browser; the responses carry no Content-Security-Policy, so inline script is not blocked.
Maintenance note
Query error strings are rendered as raw HTML by ErrorWidget::queryError() via Html::errorBox(). Any error added through Query::addErrors() that embeds user-controlled text must be output-encoded (or use a message key); pagination and validation error text is attacker-influenced and must not be treated as trusted.
Impact
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2026-77616 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (7.2.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
- Output-encode the attacker-controlled
sort_prop/sort_ordervalues before they are interpolated into the error text inQueryCreator, so no raw user input enters the error stream. - Defense in depth: the
format=debugoutput path that reflected the same error text was hardened separately in GHSA-q5fm-9mx6-44f4.
Frequently Asked Questions
- What is CVE-2026-77616? CVE-2026-77616 is a medium-severity cross-site scripting (XSS) vulnerability in mediawiki/semantic-media-wiki (composer), affecting versions >= 7.0.0, <= 7.1.0. It is fixed in 7.2.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2026-77616? CVE-2026-77616 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of mediawiki/semantic-media-wiki are affected by CVE-2026-77616? mediawiki/semantic-media-wiki (composer) versions >= 7.0.0, <= 7.1.0 is affected.
- Is there a fix for CVE-2026-77616? Yes. CVE-2026-77616 is fixed in 7.2.0. Upgrade to this version or later.
- Is CVE-2026-77616 exploitable, and should I be worried? Whether CVE-2026-77616 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-77616 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-77616? Upgrade
mediawiki/semantic-media-wikito 7.2.0 or later.