TIRESIS/Forecast/CVE-2026-55584
LOW RISK

CVE-2026-55584

phpSysInfo is a customizable PHP script that displays system information. Prior to 3.4.6, the PSI_ALLOWED access-control check in read_config.php trusts attacker-controlled X-Forwarded-For and Client-IP HTTP headers before REMOTE_ADDR. A remote unauthenticated attacker can supply…

SMB Attack Probability Score
1/100low
Weighted: EPSS · CISA KEV · SMB stack prevalence · exploit maturity · CVSS vector
CVSS v3
7.5
EPSS (30d)
—
SMB Exposure
5/100
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
💻
SMB Impact
How this vulnerability affects a real small business
1
How this breaks an SMB

Operating system vulnerability enables privilege escalation or remote code execution — giving attackers full control over affected machines within the network.

2
Typical real-world scenario

Initial foothold (phishing or exposed service) triggers OS exploit. Domain admin privileges are obtained. Ransomware is deployed network-wide overnight.

3
Estimated downtime & cost
Est. downtime
5–14 days
Business cost range
€20K–€150K
4
What IT should check this week
Are all Windows/macOS systems updated within the last 30 days?
Is Windows Defender or equivalent AV active and updated?
Are local admin rights restricted to only necessary users?
Are domain admin accounts used only for admin tasks?
Scenarios are generated based on software category and CVE characteristics. Cost ranges reflect SMB incidents in TIRESIS incident database.
Threat Evolution Timeline
From disclosure to predicted exploitation — 3 events
◈ 1 predicted
📋
28 Aug 2026
Vulnerability disclosed
CVE published by NVD with CVSS 7.5 (HIGH)
📍
TODAY
Today
EPSS: N/A probability of exploitation in next 30 days. SMB Risk Score: 1/100
Forecast →
✅
12 Nov 2026◈ predicted · in 60 days
Predicted: widespread patch adoption
Low EPSS suggests limited active exploitation. Most organizations expected to patch in routine maintenance cycle.
◈ Predicted eventsare estimates based on EPSS score, exploit maturity, and historical CVE progression patterns. They are not guaranteed outcomes.
Affected Products
composer:phpsysinfo/phpsysinfo
Remediation & References
What to do
🌐No authentication required — restrict external access nowhigh

This vulnerability can be exploited remotely without credentials or user interaction. Until patched: block access to the affected service from the internet using firewall rules or ACLs. Only allow access from trusted IPs.

NVD Full Entry ↗Official vulnerability detail, CVSS vectors, CPE listEPSS Score ↗Exploit Prediction Scoring System — FIRST.orgMitre CVE ↗MITRE CVE Program official entry
Vendor & Exploit References
Scoring Methodology

SMB Attack Probability Score weights: EPSS exploit likelihood (35%), CISA KEV active exploitation (25%), SMB stack prevalence (20%), exploit maturity (10%), CVSS network vector complexity (10%). Impact scenarios are derived from software category and historical SMB incident patterns. Scores recompute daily.