# CVE-2026-15256: Ninja Forms < 3.14.10 - Unauthenticated Arbitrary Shortcode Execution via Query-String Populated Field Default

> Unauthenticated attackers can execute arbitrary shortcodes via query-string input in Ninja Forms, potentially leading to code execution on the site.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Aug 2026
- **Updated:** 7 Aug 2026
- **Also known as:** GHSA-2xwp-m9v6-767p

## What is CVE-2026-15256?

CVE-2026-15256 is a medium-severity code injection vulnerability in Unknown Ninja Forms, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Ninja Forms WordPress plugin before 3.14.10 does not prevent user-supplied query-string input, used to pre-populate a form field's default value, from being processed as a shortcode, allowing unauthenticated attackers to execute arbitrary shortcodes registered on the site when a form so configured is embedded on a public page.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2026-15256?


## How do I fix CVE-2026-15256?

No fix has been published for CVE-2026-15256 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-15256 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15256 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-15256 and fix it if it is affected.

What it is: CVE-2026-15256 is a medium-severity code injection vulnerability in Unknown Ninja Forms, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15256 exists.

Affected product: Unknown Ninja Forms. 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-2026-15256/ (Markdown: https://insights.sbomify.com/CVE-2026-15256/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15256
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15256
- OSV: https://osv.dev/vulnerability/CVE-2026-15256

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-15256/
Summaries are generated and may contain mistakes; the official description above is the record.