CVE-2025-64203 WordPress Mailster plugin < 4.1.14 - Cross Site Scripting (XSS) vulnerability
High 7.1
Published
Updated
Check this codebase for CVE-2025-64203 and fix it if it is affected.
What it is: CVE-2025-64203 is a high-severity vulnerability in EverPress Mailster, published on 18 Dec 2025.
Exploitation: There is no known exploitation of CVE-2025-64203 in the wild and no public exploit code.
Affected product: EverPress Mailster. 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-2025-64203/ (Markdown: https://insights.sbomify.com/CVE-2025-64203/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2025-64203?
CVE-2025-64203 is a high-severity vulnerability in EverPress Mailster, published on 18 Dec 2025.
Official description
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in EverPress Mailster mailster allows Reflected XSS.This issue affects Mailster: from n/a through < 4.1.14.
Weakness: CWE-79
Which versions are affected by CVE-2025-64203?
How do I fix CVE-2025-64203?
No fix has been published for CVE-2025-64203 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-64203 being exploited?
There is no known exploitation of CVE-2025-64203 in the wild and no public exploit code.
Sources
Also known as GHSA-39f9-v6jc-j4qf.