Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-55584 high CVSS 7.5

Vulnerability in phpsysinfo/phpsysinfo (CVE-2026-55584)

Summary

Vulnerability in phpsysinfo/phpsysinfo (CVE-2026-55584). Confidential information can be exposed externally. Exploitable via PSI_ALLOWED. Mitigation: upgrade to 3.4.6 or later.

Original description

The description as published by the source.

Summary

phpSysInfo's PSI_ALLOWED IP allowlist can be trivially bypassed by any unauthenticated remote attacker. The access-control check in read_config.php derives the client IP from the attacker-controlled X-Forwarded-For and Client-IP HTTP headers before falling back to REMOTE_ADDR. An attacker can send X-Forwarded-For: to impersonate a trusted address and gain full access to all exposed system information, defeating the only IP-based access restriction the application provides.

Affected component

  • File: read_config.php
  • Versions: all versions up to and including 3.4.x (current main)

Description

When PSI_ALLOWED is configured, read_config.php enforces an IP allowlist. The client IP is resolved as follows:

if (isset($_SERVER["HTTP_X_FORWARDED_FOR"])) {
    $ip = $_SERVER["HTTP_X_FORWARDED_FOR"];
} else {
    if (isset($_SERVER["HTTP_CLIENT_IP"])) {
        $ip = $_SERVER["HTTP_CLIENT_IP"];
    } else {
        $ip = $_SERVER["REMOTE_ADDR"];
    }
}

Both HTTP_X_FORWARDED_FOR and HTTP_CLIENT_IP are fully attacker-controlled request headers. They are trusted unconditionally and take priority over REMOTE_ADDR. There is no concept of a configured/trusted reverse proxy, so even when phpSysInfo is exposed directly (no proxy in front), the spoofed header wins. As a result the allowlist provides no real protection.

Proof of Concept

Verified against phpSysInfo 3.4.x-main-d786ab2 running in a local Docker container (`php:8.…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-55584 has been found in phpsysinfo/phpsysinfo.
Attackers can target a specific entry point like PSI_ALLOWED over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: upgrade phpsysinfo/phpsysinfo to 3.4.6 or later.
If unsure, ask your IT team or search "phpsysinfo/phpsysinfo CVE-2026-55584" on the vendor's site.

CVE-2026-55584 (phpsysinfo/phpsysinfo) — CWE-290 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: PSI_ALLOWED / read_config.php / REMOTE_ADDR / main
Patched: 3.4.6 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-290) exists in phpsysinfo/phpsysinfo. Attackers reach the vulnerable code path via PSI_ALLOWED without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of phpsysinfo/phpsysinfo. Attack surface: PSI_ALLOWED / read_config.php / REMOTE_ADDR / main.

🔥 Severity

Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 3.4.6.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'phpsysinfo/phpsysinfo' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'phpsysinfo/phpsysinfo' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で phpsysinfo/phpsysinfo を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade phpsysinfo/phpsysinfo to 3.4.6

    ステージング環境で 3.4.6 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

composer phpsysinfo/phpsysinfo
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.6"}]}]
Packagist phpsysinfo/phpsysinfo
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.6"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details