45/100 CVSS 8.2 🔴 CVE ANALYSISPublished: May 5, 2026

webonyx/graphql-php has unbounded recursion in parser that causes stack overflow on crafted nested input

## Summary `GraphQL\Language\Parser` is a recursive descent parser with no recursion depth limit and no `zend.max_allowed_stack_size` interaction. Crafted nested queries trigger a SIGSEGV in the PHP runtime, killing the FPM/CLI worker process. Smallest crashing payload is approximately 74 KB. ## Affected Component - `src/Language/Parser.php` -- the...

8.2

CVSS Score

MEDIUM

Threat Level

Priority /100

TBD

Exploited ITW

Monitor

CISA Status

Sources

🔵

HIGH-PRIORITY SECURITY ADVISORY — Priority Score: 45/100

CVSS 8.2 MEDIUM. SENTINEL APEX recommends immediate patch evaluation. Intelligence from 1 confirmed source(s).

📋 Executive Summary

⚡ Analyst Assessment — SENTINEL APEX v4.0

CYBERDUDEBIVASH SENTINEL APEX has confirmed a MEDIUM-tier threat intelligence signal for GHSA-b3478999926054bf affecting composer webonyx/graphql-php. Composite threat score: 45/100. Intelligence corroborated across 1 source(s): github_advisories. CVSS base score: 8.2. Exploitation probability assessed as HIGH based on vulnerability characteristics.

Intelligence sources: github_advisories

⚠️ Business Impact Analysis

⚠️ composer webonyx/graphql-php users face material security risk requiring immediate remediation

🔗 Attack Chain Analysis

Step-by-step attack chain based on observed TTPs and vulnerability characteristics:

#	Phase	Attacker Action	MITRE
1	Reconnaissance	Attacker identifies exposed webonyx/graphql-php instances via Shodan, Censys, or targeted scanning	`TA0043`
2	Initial Access	Exploitation of GHSA-b3478999926054bf in composer webonyx/graphql-php	`T1190`
3	Persistence	Backdoor, scheduled task, or new admin account created for persistent access	`T1053`
4	Command & Control	Attacker establishes persistent C2 channel using HTTPS or DNS tunneling	`T1071`
5	Impact / Objectives	Intellectual property theft, espionage, cryptomining, or preparation for future attack stage	`T1657`

⚠ Deep Dive Analysis

This high-severity vulnerability in composer webonyx/graphql-php (CVSS 8.2) represents a significant attack surface. SENTINEL APEX assesses exploitation to be technically feasible with moderate effort. Organizations running webonyx/graphql-php in internet-facing or privileged positions face immediate risk.

SENTINEL APEX URGENCY: HIGH. 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	T1068 — Exploitation for Privilege Escalation
Weakness (CWE)	CWE-674
Intel Type	🔴 CVE ANALYSIS
Source(s)	github_advisories

🔍 Detection Rules — Sigma (SIEM)

Deploy to Splunk, Elastic, Microsoft Sentinel, or QRadar. SOC Pro subscribers receive pre-compiled SIEM-native query packs updated with each pipeline run.

Sigma YAMLtitle: GHSA-b3478999926054bf Exploitation Attempt — composer webonyx/graphql-php
id: 5d1102e26c447072-7647
status: experimental
description: Detects exploitation of GHSA-b3478999926054bf in composer webonyx/graphql-php. Priority: MEDIUM. Score: 45/100
author: CYBERDUDEBIVASH SENTINEL APEX v4.0 (bivash@cyberdudebivash.com)
date: 2026-05-05
references:
    - https://nvd.nist.gov/vuln/detail/GHSA-b3478999926054bf
    - https://blog.cyberdudebivash.in/
tags:
    - attack.initial_access
    - attack.t1190
logsource:
    category: webserver
detection:
    keywords:
        - 'ghsa-b3478999926054bf'
    condition: keywords
falsepositives:
    - Security scanners
level: high

📡 Detection Rules — YARA (Endpoint)

Deploy to endpoint detection platforms. Enterprise subscribers receive tuned, FP-validated YARA rule packs.

YARArule GHSA_b3478999926054bf_Exploitation {
    meta:
        description = "Detects artifacts related to GHSA-b3478999926054bf exploitation in composer webonyx/graphql-php"
        author      = "CYBERDUDEBIVASH SENTINEL APEX v4.0"
        date        = "2026-05-05"
        severity    = "HIGH"
        cvss        = "8.2"
        priority    = "45/100"
        threat_level = "MEDIUM"
        reference   = "https://nvd.nist.gov/vuln/detail/GHSA-b3478999926054bf"
    strings:
        $id_str  = "GHSA-b3478999926054bf" ascii nocase
        $product = "webonyx_graphql_php" ascii nocase wide
    condition:
        any of them
}

🛡️ SOC Response Playbook

1IMMEDIATE (0-1hr): Identify all instances of webonyx/graphql-php in your environment via CMDB/asset inventory
2IMMEDIATE (0-1hr): Apply vendor patch — no maintenance window exception for MEDIUM threats
3IMMEDIATE (1-2hr): If no patch available: implement WAF rules, ACLs, or network-level compensating controls
4SHORT-TERM (2-4hr): Deploy Sigma detection rule to SIEM — validate alert generation in test environment
5SHORT-TERM (4-8hr): Review logs for exploitation indicators (anomalous webonyx/graphql-php requests, error spikes)
6SHORT-TERM (8-24hr): Hunt for post-exploitation: new admin accounts, scheduled tasks, lateral movement
7MONITOR: Subscribe to composer security advisories for patch updates
8ONGOING: Track SENTINEL APEX intelligence feed for follow-on campaigns targeting webonyx/graphql-php

📎 Intelligence References

SENTINEL INTEL BRIEF

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⚡ CYBERDUDEBIVASH SENTINEL APEX v4.0

Intelligence report generated by CYBERDUDEBIVASH SENTINEL APEX v4.0
Report ID: SENTINEL-GHSA-b3478999926054bf-2026-05-05 | Priority: 45/100 MEDIUM | Sources: 1
© 2026 CYBERDUDEBIVASH PRIVATE LIMITED
Republication requires written attribution to CYBERDUDEBIVASH SENTINEL APEX

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