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Authenticated Remote Code Execution via unsanitized HTTP_REFERER (CVE-2025-6213)

High
hsntgm published GHSA-636g-ww4c-2j54 Jul 23, 2025

Package

psaux-it/nginx-fastcgi-cache-purge-and-preload (wordpress-plugin)

Affected versions

<= 2.1.2

Patched versions

2.1.3

Description

Impact

This is a Remote Code Execution (RCE) vulnerability affecting the Nginx Cache Purge Preload plugin for WordPress, in all versions up to and including v2.1.2.

An authenticated attacker with Administrator privileges could exploit unsanitized use of the $_SERVER['HTTP_REFERER'] header in the nppp_preload_cache_on_update() function. The value was passed into a shell command using shell_exec() without proper validation or escaping, enabling arbitrary command execution on the server.

Researcher: cynau1t (TianGong)

Patches

The vulnerability was fully patched in version v2.1.3.
To prevent exploitation, the following mitigations were implemented:

  1. ✅ Sanitized using esc_url_raw( wp_unslash(...) )
  2. ✅ Validated URL using FILTER_VALIDATE_URL
  3. ✅ Enforced same-origin policy by comparing the referrer domain with home_url() via wp_parse_url()
  4. ✅ Use escapechellarg

Patch commits: efdd1bf 712d737 f5ab194 8a9fa74 9b2f251

All versions up to and including v2.1.2 are affected.
Users should upgrade to version v2.1.3 or later immediately to remain secure.

Workarounds

There is no safe workaround for this vulnerability in affected versions. Disabling admin-bar cache actions or removing nppp_preload_cache_on_update() manually will break plugin, and it is not recommended.

The only reliable remediation is to upgrade to version v2.1.3 or later.

References

🔒 CVE: CVE-2025-6213
🧠 Wordfence advisory: wordfence.com
📦 GitHub Advisory: GHSA-7653-r8cq-rf8w

Patch commits: efdd1bf 712d737

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

CVE ID

CVE-2025-6213

Weaknesses

Improper Control of Generation of Code ('Code Injection')

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Learn more on MITRE.