# CVE-2025-4126: EG-Series <= 2.1.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode

> Authenticated attackers can inject arbitrary JavaScript via shortcode attributes, leading to stored XSS execution on affected WordPress sites.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 May 2025
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-47qp-9grv-hjc7

## What is CVE-2025-4126?

CVE-2025-4126 is a medium-severity cross-site scripting vulnerability in emmanuelg EG-Series, published on 15 May 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The EG-Series plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's [series] shortcode in all versions up to, and including, 2.1.1 due to insufficient input sanitization and output escaping on user supplied attributes in the shortcode_title function. This makes it possible for authenticated attackers - with contributor-level access and above, on sites with the Classic Editor plugin activated - to inject arbitrary JavaScript code in the titletag attribute that will execute whenever a user access an injected page.

Weakness: CWE-80 (Improper Neutralization of Script-Related HTML Tags in a Web Page)

## Which versions are affected by CVE-2025-4126?


## How do I fix CVE-2025-4126?

No fix has been published for CVE-2025-4126 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-4126 being exploited?

There is no known exploitation of CVE-2025-4126 in the wild and no public exploit code.

Public exploit code:

- smart contract reentrancy attack vulnerability POC (github_poc): https://github.com/Slow-Mist/CVE-2025-4126

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-4126 and fix it if it is affected.

What it is: CVE-2025-4126 is a medium-severity cross-site scripting vulnerability in emmanuelg EG-Series, published on 15 May 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-4126 in the wild and no public exploit code.

Affected product: emmanuelg EG-Series. 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-2025-4126/ (Markdown: https://insights.sbomify.com/CVE-2025-4126/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-4126
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-4126
- OSV: https://osv.dev/vulnerability/CVE-2025-4126

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-4126/
Summaries are generated and may contain mistakes; the official description above is the record.