PhpSpreadsheet has SSRF/RCE in IOFactory::load when $filename is user controlled
The usage of `is_file`, used to verify if the `$filename` is indeed an actual file, by all(?) `Reader` implementations (inside the helper function `File::assertFile`) is php-wrapper aware, for any [php wrappers](https://www.php.net/manual/en/wrappers.php) implementing `stat()`. The 3 wrappers `ftp://`, `phar://` and `ssh2.sftp://`, all satisfy this...
CVSS 7.5 MEDIUM. SENTINEL APEX recommends immediate patch evaluation. Intelligence from 1 confirmed source(s).
📋 Executive Summary
This report analyzes CVE-2026-34084 affecting composer phpoffice/phpspreadsheet. Composite threat score: 45/100. Intelligence corroborated across 1 source(s): github_advisories. CVSS base score: 7.5. No confirmed in-the-wild exploitation at the time of writing; prioritize on exposure, privilege, and CVSS.
⚠️ Business Impact Analysis
- ⚠️ Remote code execution — full server takeover without authentication possible
- ⚠️ Privilege escalation — local attacker can become SYSTEM/root
🔗 Representative Attack Path
A typical attack path for this vulnerability class, mapped to MITRE ATT&CK — a representative model to guide detection and defense, not a claim of observed activity against a specific target. Confirm specifics against the primary sources below.
| # | Phase | Attacker Action | MITRE |
|---|---|---|---|
1 |
Reconnaissance | Attacker identifies exposed phpoffice/phpspreadsheet instances via Shodan, Censys, or targeted scanning | TA0043 |
2 |
Initial Access | Exploitation of CVE-2026-34084 in composer phpoffice/phpspreadsheet | T1190 |
3 |
Execution | Remote code execution achieved — attacker runs arbitrary commands on target system | T1203 |
4 |
Privilege Escalation | Local privilege escalation to SYSTEM/root for full control | T1068 |
5 |
Persistence | Backdoor, scheduled task, or new admin account created for persistent access | T1053 |
6 |
Command & Control | Attacker establishes persistent C2 channel using HTTPS or DNS tunneling | T1071 |
7 |
Impact / Objectives | Intellectual property theft, espionage, cryptomining, or preparation for future attack stage | T1657 |
⚠ Deep Dive Analysis
This high-severity vulnerability in composer phpoffice/phpspreadsheet (CVSS 7.5) represents a significant attack surface. SENTINEL APEX assesses exploitation to be technically feasible with moderate effort. Organizations running phpoffice/phpspreadsheet in internet-facing or privileged positions face immediate risk.
SENTINEL APEX URGENCY: ELEVATED. Score: 45/100 MEDIUM. Patch before exploitation activity begins.
🎯 MITRE ATT&CK Mapping
| Category | Mapping |
|---|---|
| Primary Tactic | Execution |
| Primary Technique | T1203 — Exploitation for Client Execution |
| Sub-Technique | T1059 — Command & Scripting Interpreter |
| Weakness (CWE) | CWE-502 |
| Intel Type | 🔴 CVE ANALYSIS |
| Source(s) | github_advisories |
🔴 CVE Reference
| CVE ID | Reference | Score |
|---|---|---|
| CVE-2026-34084 | NVD → | 7.5 |
| CVE-2026-34084 | NVD → | 7.5 |
🏷️ Indicators of Compromise — Enriched IOC Feed
Normalized IOCs with confidence scoring. Block immediately across all enforcement points. SOC Pro subscribers receive enriched IOC bundles with full attribution and STIX/TAXII feeds.
| Indicator Value | Type | Confidence | First Seen |
|---|---|---|---|
| https://www.php.net/manual/en/wrappers.php) | url | 82% | 2026-04-29 |
| www.php.net | domain | 75% | 2026-04-29 |
🔍 Detection Rules — Sigma (SIEM)
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📡 Detection Rules — YARA (Endpoint)
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🛡️ SOC Response Playbook
- 1IMMEDIATE (0-1hr): Identify all instances of phpoffice/phpspreadsheet in your environment via CMDB/asset inventory
- 2IMMEDIATE: Block all 2 IOCs in this report at firewall, proxy, DNS, and EDR simultaneously
- 3IMMEDIATE (0-1hr): Apply vendor patch — no maintenance window exception for MEDIUM threats
- 4IMMEDIATE (1-2hr): If no patch available: implement WAF rules, ACLs, or network-level compensating controls
- 5SHORT-TERM (2-4hr): Deploy Sigma detection rule to SIEM — validate alert generation in test environment
- 6SHORT-TERM (4-8hr): Review logs for exploitation indicators (anomalous phpoffice/phpspreadsheet requests, error spikes)
- 7SHORT-TERM (8-24hr): Hunt for post-exploitation: new admin accounts, scheduled tasks, lateral movement
- 8MONITOR: Subscribe to composer security advisories for patch updates
- 9ONGOING: Track SENTINEL APEX intelligence feed for follow-on campaigns targeting phpoffice/phpspreadsheet
📎 Intelligence References
- github.com/advisories/GHSA-q4q6-r8wh-5cgh
- github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-q4q6-r8wh
- www.php.net/manual/en/wrappers.php
- github.com/advisories/GHSA-q4q6-r8wh-5cgh
- 📌 NVD — CVE-2026-34084
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Report ID: SENTINEL-CVE-2026-34084-2026-04-29 | Priority: 45/100 MEDIUM | Sources: 1
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