# CVE-2026-19804: s2Member <= 260814 - Unauthenticated Remote Code Execution via 'first_name' Parameter in PayPal Proxy Return

> Unauthenticated attackers can execute arbitrary code on WordPress sites using the s2Member plugin if a specific tracking template is configured and the proxy key is exposed.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 25 Sep 2026
- **Updated:** 25 Sep 2026
- **Also known as:** GHSA-fgx2-6hhq-hwhw

## What is CVE-2026-19804?

CVE-2026-19804 is a high-severity code injection vulnerability in clavaque s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions, published on 25 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 260814 via the 'first_name' parameter parameter. This is due to insufficient sanitization of the first_name parameter via esc_refs(), which strips only regex backreferences and not PHP tags, before substitution into the eval'd Signup Tracking Codes template, combined with disclosure of the site-global proxy verification key that allows PayPal postback verification to be bypassed. This makes it possible for unauthenticated attackers to execute code on the server. Successful exploitation requires that the site administrator has configured a Signup Tracking Codes template containing the %%first_name%% placeholder (a documented, GUI-supported feature) and that the attacker has obtained the site-global proxy verification key, which is exposed in plaintext in the JSON response of any PayPal Checkout AJAX request on the target site.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-19804?


## How do I fix CVE-2026-19804?

No fix has been published for CVE-2026-19804 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-19804 being exploited?

There is no known exploitation of CVE-2026-19804 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-19804 and fix it if it is affected.

What it is: CVE-2026-19804 is a high-severity code injection vulnerability in clavaque s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions, published on 25 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-19804 in the wild and no public exploit code.

Affected product: clavaque s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions. 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-2026-19804/ (Markdown: https://insights.sbomify.com/CVE-2026-19804/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-19804
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-19804
- OSV: https://osv.dev/vulnerability/CVE-2026-19804

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-19804/
Summaries are generated and may contain mistakes; the official description above is the record.