CVE-2025-26879
Published: 03 March 2025
Summary
CVE-2025-26879 is a high-severity Cross-site Scripting (CWE-79) vulnerability. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 43.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-15 (Information Output Filtering).
Deeper analysis
CVE-2025-26879 is an Improper Neutralization of Input During Web Page Generation vulnerability, classified as Reflected Cross-site Scripting (XSS) under CWE-79, in the s2Member WordPress plugin developed by Cristián Lávaque. This issue affects s2Member versions from n/a through <= 241216. The vulnerability was published on 2025-03-03T14:15:56.213 and carries a CVSS v3.1 base score of 7.1 (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L).
Attackers can exploit this vulnerability remotely over the network with low attack complexity and no required privileges, though it necessitates user interaction such as clicking a malicious link. Upon successful exploitation, adversaries achieve low impacts on confidentiality, integrity, and availability, with a changed scope that elevates the potential effects through the reflected payload, such as session hijacking or phishing within the context of affected WordPress sites.
The primary advisory from Patchstack, available at https://patchstack.com/database/Wordpress/Plugin/s2member/vulnerability/wordpress-s2member-plugin-241216-reflected-cross-site-scripting-xss-vulnerability?_s_id=cve, documents the Reflected XSS vulnerability in the s2Member plugin version 241216. Mitigation guidance emphasizes updating to a version beyond the affected range (<= 241216) to address the input neutralization flaw.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-5614
Vulnerability details
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Cristián Lávaque s2Member s2member allows Reflected XSS.This issue affects s2Member: from n/a through <= 241216.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Reflected XSS in public-facing WordPress plugin directly maps to T1190 for initial exploitation of the web application; enables T1539 for stealing session cookies to achieve session hijacking as described in the impact.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
SI-15 directly addresses reflected XSS by requiring filtering and encoding of information outputs to neutralize untrusted input during web page generation.
SI-10 prevents exploitation by validating all user inputs to block malicious scripts from being processed in the s2Member plugin.
SI-2 mitigates the vulnerability through timely flaw remediation, such as updating the s2Member plugin beyond version 241216.