Quick answers
- Is CVE-2026-19804 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-19804 being exploited in the wild.
- How severe is CVE-2026-19804?
- High severity, with a CVSS score of 8.8, published 25 September 2026.
- Which products and versions are affected?
- s2Member up to and including 260814.
- Is there a fix for CVE-2026-19804?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-19804 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-19804?
- Check whether you run s2Member at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The plugin's esc_refs() sanitization function strips only PHP regex backreferences but not PHP tags before substituting user input into an eval'd template containing %%first_name%% placeholders. Combined with plaintext disclosure of the site-global proxy verification key in PayPal Checkout AJAX responses, an unauthenticated attacker can bypass PayPal postback verification and inject PHP code into the signup tracking template. Successful exploitation requires the administrator to have enabled Signup Tracking Codes with the documented %%first_name%% placeholder feature.
Affected products
- s2Member s2Member up to and including 260814
Timeline
- 2026-09-25: disclosed