CVE-2025-58998

s2Member <= 250701 - Unauthenticated PHP Object Injection

2025-08-21 00:00

Strategic Overview

Status: Patched in 250905
Affected Plugin: s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions
Affected Version: <= 250701
CVSS: 8.1High
Weakness type: CWE-502 · Deserialization of Untrusted Data
CVE: CVE-2025-58998

View all s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions vulnerabilities

At a glance

CVE-2025-58998 is a high-severity Deserialization of Untrusted Data vulnerability in the s2Member WordPress plugin, affecting versions <= 250701. It carries a CVSS score of 8.1 (reachable over the network; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 250905; sites on affected versions should update now. Disclosed August 2025, reported by ChuongVN.

Vulnerability Overview

The s2Member plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 250701 via deserialization of untrusted input. This makes it possible for unauthenticated attackers to inject a PHP Object. No known POP chain is present in the vulnerable software. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-502: Deserialization of Untrusted Data

Reaching this weakness in s2Member <= 250701 takes no account at all. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.

A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For s2Member the fix is 250905: builds <= 250701 are affected, anything from 250905 onward is not.

Remediation

Update to version 250905, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: s2Member 250905 closes this, and updating the plugin is the step that ends it.

Firewall
Scanner
Login Security

External References

https://www.cve.org/CVERecord?id=CVE-2025-58998 https://www.wordfence.com/threat-intel/vulnerabilities/id/5e24e99a-2981-4f3e-a672-10f57cf96675 https://nvd.nist.gov/vuln/detail/CVE-2025-58998

Related records

Other vulnerabilities in s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions

CVSS Vector

8.1

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Base

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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