CVE-2026-55372

NukeViet: Pre-authentication SSRF via X-Forwarded-Host

$proto = $nv_Server->getOriginalProtocol();   // from X-Forwarded-Proto
$host  = $nv_Server->getOriginalHost();        // from X-Forwarded-Host
$ch = curl_init($proto . '://' . $host . NV_BASE_SITEURL . 'index.php?response_headers_detect=1');
curl_exec($ch);

POST /index.php HTTP/1.1
Host: <victim>
X-Forwarded-Proto: http
X-Forwarded-Host: <attacker-controlled-host>:<port>/
Content-Type: application/x-www-form-urlencoded
Content-Length: 20

__serverInfoUpdate=1

The SSRF is blind, HEAD-only, and uses a fixed request path (…/index.php?response_headers_detect=1):

• The fetched response is stored server-side in the config_ini cache and is not reflected to the attacker, so internal data cannot be exfiltrated directly.
• Because the path is fixed and not attacker-controlled, cloud metadata endpoints (e.g. 169.254.169.254/latest/meta-data/...) cannot be reached, and gopher:// / dict:// request smuggling cannot inject arbitrary payloads.

What an attacker can do: unauthenticated internal host/port discovery (connection success/timing, with the port reachable through the regex bypass), and poisoning of the cached server_headers (the SSRF target's response headers are stored and applied to the site).

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-2026-55372 has a CVSS score of 7.2 (High). The vector is network-reachable, no 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 (4.6.00); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

Fixed by validating and normalising the forwarded values at the source and gating the request before the sink:

• standardizeHost() now extracts the host with parse_url() (defeats the :port/ bypass) and lower-cases it.
• X-Forwarded-Proto is restricted to a {http, https} allow-list and falls back to the real server protocol otherwise.
• X-Forwarded-Port is validated as numeric and within range.
• The incoming host is checked against my_domains before includes/ini.php is reached; non-matching hosts are rejected/redirected, and server_info_update() additionally re-validates its target host against my_domains (defense in depth).

1. What is CVE-2026-55372? CVE-2026-55372 is a high-severity server-side request forgery (SSRF) vulnerability in nukeviet/nukeviet (composer), affecting versions < 4.6.00. It is fixed in 4.6.00. 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-2026-55372? CVE-2026-55372 has a CVSS score of 7.2 (High). 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 nukeviet/nukeviet are affected by CVE-2026-55372? nukeviet/nukeviet (composer) versions < 4.6.00 is affected.
4. Is there a fix for CVE-2026-55372? Yes. CVE-2026-55372 is fixed in 4.6.00. Upgrade to this version or later.
5. Is CVE-2026-55372 exploitable, and should I be worried? Whether CVE-2026-55372 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-2026-55372 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-2026-55372? Upgrade nukeviet/nukeviet to 4.6.00 or later.

Other vulnerabilities in nukeviet/nukeviet