# CVE-2026-113683: VPL for Moodle before 5.0.0 Reflected XSS via similarity/diff.php filename


- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 20 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** GHSA-2929-5xr7-ghmp

## What is CVE-2026-113683?

CVE-2026-113683 is a medium-severity vulnerability in jcrodriguez-dis moodle-mod_vpl, published on 20 Oct 2026. 

### Official description

VPL (Virtual Programming Lab) for Moodle before 5.0.0 contains a reflected cross-site scripting vulnerability that allows remote attackers to inject script via unencoded filename1/filename2 parameters in similarity/diff.php. Attackers can craft a diff.php link with a JavaScript payload that runs when a user holding mod/vpl:similarity opens it, performing actions or disclosing data under their session.

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

## Which versions are affected by CVE-2026-113683?


## How do I fix CVE-2026-113683?

No fix has been published for CVE-2026-113683 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-113683 being exploited?

There is no known exploitation of CVE-2026-113683 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-113683 and fix it if it is affected.

What it is: CVE-2026-113683 is a medium-severity vulnerability in jcrodriguez-dis moodle-mod_vpl, published on 20 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-113683 in the wild and no public exploit code.

Affected product: jcrodriguez-dis moodle-mod_vpl. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-113683/ (Markdown: https://insights.sbomify.com/CVE-2026-113683/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-113683
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-113683
- OSV: https://osv.dev/vulnerability/CVE-2026-113683

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-113683/
Summaries are generated and may contain mistakes; the official description above is the record.