# CVE-2026-77610: Semantic MediaWiki has a query debug output XSS (`DebugFormatter`)

> Reflected XSS in Semantic MediaWiki allows attackers to execute arbitrary scripts via unescaped query debug output, requiring no special privileges.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **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:** Yes
- **Published:** 18 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-q5fm-9mx6-44f4

## What is CVE-2026-77610?

CVE-2026-77610 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. Prior to version 7.2.0, query debug output (`format=debug`, or the `debug` request parameter on `Special:Ask`) is assembled by `SMW\Query\DebugFormatter` and emitted as raw HTML. Several of its sinks apply no output-context encoding, so attacker-controlled query input is reflected into the page without escaping. On `Special:Ask` the resulting string is concatenated into the page and sent through `OutputPage::addHTML`, never through the MediaWiki parser or Sanitizer. No special user right is required; an anonymous request suffices. This is a reflected XSS: the payload is taken from the request and echoed in the same response. Exploitation requires the query condition to target a text/blob-typed property (whose value is re-serialized verbatim); the predefined `_txt` properties (`Text`, etc.) that ship on every install satisfy this, so no attacker-created content is needed. Version 7.2.0 patches the issue.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-77610?

2 open source packages ship an affected version, including mediawiki/semantic-media-wiki.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mediawiki/semantic-media-wiki` | Packagist | All versions | 7.2.0 |
| `mediawiki/semantic-media-wiki` | Packagist | All versions | 7.2.0 |

## How do I fix CVE-2026-77610?

Upgrade mediawiki/semantic-media-wiki to 7.2.0 or later.

## Is CVE-2026-77610 being exploited?

There is no known exploitation of CVE-2026-77610 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77610 and fix it if it is affected.

What it is: CVE-2026-77610 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.
Exploitation: There is no known exploitation of CVE-2026-77610 in the wild and no public exploit code.

Affected packages and fixed versions:
- mediawiki/semantic-media-wiki (Packagist): affected all versions; fixed in 7.2.0
- mediawiki/semantic-media-wiki (Packagist): affected all versions; fixed in 7.2.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-77610/ (Markdown: https://insights.sbomify.com/CVE-2026-77610/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77610
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77610
- OSV: https://osv.dev/vulnerability/CVE-2026-77610

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77610/
Summaries are generated and may contain mistakes; the official description above is the record.