# CVE-2026-107887: Advanced Twenty Seventeen <= 1.3.1 - Subscriber+ Site Theme Switch via ats_create_child_theme


- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 24 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** GHSA-q8c9-qpq5-4xhg

## What is CVE-2026-107887?

CVE-2026-107887 is a medium-severity vulnerability in Unknown Advanced Twenty Seventeen, published on 24 Oct 2026. 

### Official description

The Advanced Twenty Seventeen WordPress plugin through 1.3.1 does not perform any capability or nonce check on the action that creates and activates its bundled child , allowing any authenticated user such as a subscriber to switch the site's active  site-wide, and allowing the same action to be triggered against any logged-in user including an administrator via CSRF.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-107887?


## How do I fix CVE-2026-107887?

No fix has been published for CVE-2026-107887 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-107887 being exploited?

There is no known exploitation of CVE-2026-107887 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-107887 and fix it if it is affected.

What it is: CVE-2026-107887 is a medium-severity vulnerability in Unknown Advanced Twenty Seventeen, published on 24 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-107887 in the wild and no public exploit code.

Affected product: Unknown Advanced Twenty Seventeen. 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-2026-107887/ (Markdown: https://insights.sbomify.com/CVE-2026-107887/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-107887
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107887
- OSV: https://osv.dev/vulnerability/CVE-2026-107887

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-107887/
Summaries are generated and may contain mistakes; the official description above is the record.