s2Member <= 260814 — Unauthenticated Remote Code Execution via 'first_name' Parameter in PayPal Proxy Return
CVE-2026-19804Published · Updated Action summary
Affected: ≤260814Update to 260829 or newer
All remediation steps- Severity
- High8.8
- CVSS
- 8.8CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:LPrivileges required- Low
UI:NUser interaction- None
S:UScope- Unchanged
C:HConfidentiality- High
I:HIntegrity- High
A:HAvailability- High
- Required access
- Unknown
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page8
Am I affected?
- Affected≤ 260814
- Patched in260829
Update to 260829 or newer.
You are affected if you run ≤ 260814. Version 260829 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions.
- No admin access? Run a passive check of your site. It reads public files only.
What to do
- Update to version 260829, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to Supakiad S. (m3ez).
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.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Related CVEs
More in s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions
All 16| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Critical9.8 | Unauthenticated Remote Code Execution via 'item_name' IPN Parameter ≤260927Update to 261001 | CVE-2026-86596 | |
| Medium6.4 | Authenticated (Contributor+) Stored Cross-Site Scripting via 'date_format' Shortcode Attribute ≤261011Update to 261017 | CVE-2026-109972 | |
| Medium6.4 | Authenticated (Contributor+) Stored Cross-Site Scripting ≤260804Update to 260805 | CVE-2026-15047 | |
| Critical9.8 | Unauthenticated Privilege Escalation via Account Takeover ≤260127Update to 260215 | CVE-2026-1994 | |
| Medium6.4 | Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode ≤251005Update to 260101 | CVE-2025-13732 |
- Critical9.8Unauthenticated Remote Code Execution via 'item_name' IPN Parameter
≤260927Update to 261001
- Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting via 'date_format' Shortcode Attribute
≤261011Update to 261017
- Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting
≤260804Update to 260805
- Critical9.8Unauthenticated Privilege Escalation via Account Takeover
≤260127Update to 260215
- Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode
≤251005Update to 260101
Timeline
CVE published
Severity high, CVSS 8.8
Record last updated
Sources & licenses
Wordfence record- Vulnerability data
- Wordfence Intelligence. [object Object] Licensed under the CC BY-SA 4.0.
- CVE® identifiers
- [object Object]. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
- CVSS / CWE
- National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.