What is the CVSS score of CVE-2026-23524?

CVE-2026-23524 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.5%.

How to fix or mitigate CVE-2026-23524?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. Restrict deserialization to trusted data sources and implement integrity checks.

Laravel CVE-2026-23524

Q: Which versions of Laravel are affected by CVE-2026-23524?

CVE-2026-23524 presents critical security risk, a insecure deserialization vulnerability rated CVSS 9.8.. A patch is available.

CRITICAL

Deserialization of Untrusted Data (CWE-502)

2026-01-21 security-advisories@github.com

GHSA-m27r-m6rx-mhm4

RCE Deserialization Laravel Redis Reverb

9.8

CVSS 3.1 · GitHub Advisory

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Deploy Laravel Reverb with horizontal scaling enabled
Delivery

Connect to unauthenticated Redis server
Exploit

Inject malicious serialized PHP object into Redis channel
Execution

Application deserializes data with unserialize()
Persist

Instantiate arbitrary class for code execution
Impact

Execute remote commands as web server user

Vulnerability Assessment

Weakness	CWE CWE-502 OWASP Top 10:2025 A08:2025 - Software or Data Integrity Failures ASVS 5.0 V1 - Encoding and Sanitization Safe deserialization, type allowlists MITRE ATT&CK 2 techniques across 2 tactics: Execution, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	Laravel Reverb versions 1.6.3 and below with REVERB_SCALING_ENABLED=true AND unauthenticated Redis server accessible on network. Horizontal scaling must be explicitly enabled in Reverb configuration.
Impact	CVSS 9.8 with patch available. Laravel Reverb is the official WebSocket server for Laravel — widely adopted in the Laravel ecosystem. Deserialization attacks can chain PHP gadgets for reliable RCE.
Exploit ScenarioDerived	An attacker connects to the Laravel Reverb WebSocket endpoint and sends a crafted message containing a serialized PHP object chain that, upon deserialization, executes arbitrary PHP code on the server.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

Patch available 0.5% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Laravel Reverb WebSocket server versions 1.6.3 and below have an insecure deserialization vulnerability enabling remote code execution on the backend server.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 9.8

Insecure deserialization in Laravel Reverb WebSocket server enables RCE.

RemediationAI

Update Laravel Reverb to version 1.6.4 or later. Implement input validation on WebSocket messages.

Affected Packages

composer laravel/reverb fix: 1.7.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in composer

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Laravel Reverb <= 1.6.3 deserializes untrusted data from WebSocket messages (CWE-502), allowing attackers to craft serialized PHP objects that execute arbitrary code during deserialization.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Patch released

Mar 06, 2026 - 20:02 nvd

Patch available

CVE Published

Jan 21, 2026 - 22:15 nvd

CRITICAL 9.8

DescriptionGitHub Advisory

Laravel Reverb provides a real-time WebSocket communication backend for Laravel applications. In versions 1.6.3 and below, Reverb passes data from the Redis channel directly into PHP’s unserialize() function without restricting which classes can be instantiated, which leaves users vulnerable to Remote Code Execution. The exploitability of this vulnerability is increased because Redis servers are commonly deployed without authentication, but only affects Laravel Reverb when horizontal scaling is enabled (REVERB_SCALING_ENABLED=true). This issue has been fixed in version 1.7.0. As a workaround, require a strong password for Redis access and ensure the service is only accessible via a private network or local loopback, and/or set REVERB_SCALING_ENABLED=false to bypass the vulnerable logic entirely (if the environment uses only one Reverb node).

Executive ViewAI

Why It Matters

CVE-2026-23524 presents critical security risk, a insecure deserialization vulnerability rated CVSS 9.8. Insecure deserialization could allow attackers to execute arbitrary code by providing crafted serialized data. A patch is available and should be applied immediately given the critical severity.

Business Impact: Severe

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Restrict deserialization endpoints; (2) Implement integrity checks on serialized data; (3) Use type-safe alternatives.

Threat Intelligence Overview

EPSS Score

0.5%

Top 33% exploitable

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC No

EPSS 0.5%

Patch available Yes

Active threat No

Deciding rule

CRITICAL severity

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Out-of-Cycle

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Very High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +49

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Insecure Deserialization CRITICAL

Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.