CVE-2026-23524: Laravel/reverb Laravel Redis Horizontal Scaling Insecure Vulnerability

CRITICAL
Advisory Identifier: GHSA-m27r-m6rx-mhm4
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CVSS 9.8
CWE-502
Published
Advisory Summary

CVE-2026-23524 is a CRITICAL (CVSS 9.8) laravel redis horizontal scaling insecure vulnerability (CWE-502: Deserialization of Untrusted Data) affecting Laravel/reverb libraries in the Packagist ecosystem. The issue involves laravel redis horizontal scaling insecure deserialization. Remediation is available by upgrading affected packages to version 1.7.0.

CVE-2026-23524 at a Glance

CVE Identifier CVE-2026-23524
GHSA Identifier GHSA-m27r-m6rx-mhm4
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-502: Deserialization of Untrusted Data
Affected Product Laravel/reverb
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-23524

To remediate this vulnerability, upgrade all affected Laravel/reverb dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

laravel/reverb fixed: 1.7.0 
Upgrade laravel/reverb to 1.7.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for laravel/reverb

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-23524, inspect your project dependencies for Laravel/reverb:

inspect dependencies for laravel/reverb

Analyze the terminal output to locate any version of Laravel/reverb in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.7.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In Laravel/reverb, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact This vulnerability affects Laravel Reverb versions prior to v1.7.0 when horizontal scaling is enabled (`REVERB_SCALING_ENABLED=true`). The exploitability of this vulnerability is increased because Redis servers are commonly deployed without authentication. With horizontal scaling enabled, Reverb servers communicate via Redis PubSub. Reverb previously passed data from the Redis channel directly into PHP’s `unserialize()` function without restricting which classes could be instantiated. **Risk:** Remote Code Execution (RCE) ### Patches This vulnerability is fixed in Laravel Reverb v1.7.0. Update your dependency to `laravel/reverb: ^1.7.0` immediately. ### Workarounds If you cannot upgrade to v1.7.0, you should apply the following mitigations: * Redis Security: Require a strong password for Redis access and ensure the service is only accessible via a private network or local loopback. * Disable Scaling: If your environment uses only one Reverb node, set `REVERB_SCALING_ENABLED=false` to bypass the vulnerable logic entirely. ### Credits This vulnerability was discovered and responsibly reported by Mohammad Yaser Abo-Elmaaty @m0h4mmad

CVE-2026-23524 Affected Laravel/reverb Versions

1 component(s)
Fixed Versions:
1.7.0
Product / Package Ecosystem Affected Versions Fixed Version
laravel/reverb
 Packagist
< 1.7.0
1.7.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/laravel/reverb/security/advisories/GHSA-m27r-m6rx-mhm4
NVD — CVE-2026-23524 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23524
Security Fix Commit FIX COMMIT
https://github.com/laravel/reverb/commit/9ec26f8ffbb701f84920dd0bb9781a1797591f1a
Laravel/reverb Source Repository REPOSITORY
https://github.com/laravel/reverb
Laravel/reverb Release RELEASE
https://github.com/laravel/reverb/releases/tag/v1.7.0
laravel.com/docs/12.x/reverb WEB
https://laravel.com/docs/12.x/reverb#scaling
laravel.com/docs/reverb WEB
https://laravel.com/docs/reverb#scaling

Frequently Asked Questions

What is CVE-2026-23524?
CVE-2026-23524 is a security vulnerability in Laravel/reverb involving Laravel Redis Horizontal Scaling Insecure Deserialization under CWE-502: Deserialization of Untrusted Data.
Which Laravel/reverb versions are affected?
Affected versions include releases prior to 1.7.0 across affected packages: laravel/reverb.
What version fixes CVE-2026-23524?
Upgrading to 1.7.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is laravel/reverb affected?
Yes, laravel/reverb is affected in releases prior to 1.7.0. Upgrade your dependency to 1.7.0 or later.
What is the CVSS score of CVE-2026-23524?
CVE-2026-23524 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-23524?
CVE-2026-23524 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).
How can I check Packagist dependencies for CVE-2026-23524?
Run the dependency tree command: 'inspect dependencies for laravel/reverb'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-m27r-m6rx-mhm4",
  "modified" : "2026-01-22T15:39:36Z",
  "published" : "2026-01-21T15:40:24Z",
  "aliases" : [ "CVE-2026-23524" ],
  "summary" : "Laravel Redis Horizontal Scaling Insecure Deserialization",
  "details" : "### Impact\n\nThis vulnerability affects Laravel Reverb versions prior to v1.7.0 when horizontal scaling is enabled (`REVERB_SCALING_ENABLED=true`).\n\nThe exploitability of this vulnerability is increased because Redis servers are commonly deployed without authentication.\n\nWith horizontal scaling enabled, Reverb servers communicate via Redis PubSub. Reverb previously passed data from the Redis channel directly into PHP’s `unserialize()` function without restricting which classes could be instantiated.\n\n**Risk:** Remote Code Execution (RCE)\n\n### Patches\nThis vulnerability is fixed in Laravel Reverb v1.7.0.\n\nUpdate your dependency to `laravel/reverb: ^1.7.0` immediately.\n\n### Workarounds\nIf you cannot upgrade to v1.7.0, you should apply the following mitigations:\n\n* Redis Security: Require a strong password for Redis access and ensure the service is only accessible via a private network or local loopback.\n* Disable Scaling: If your environment uses only one Reverb node, set `REVERB_SCALING_ENABLED=false` to bypass the vulnerable logic entirely.\n\n### Credits\nThis vulnerability was discovered and responsibly reported by Mohammad Yaser Abo-Elmaaty @m0h4mmad",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "laravel/reverb"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.7.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/laravel/reverb/security/advisories/GHSA-m27r-m6rx-mhm4"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-23524"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/laravel/reverb/commit/9ec26f8ffbb701f84920dd0bb9781a1797591f1a"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/laravel/reverb"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/laravel/reverb/releases/tag/v1.7.0"
  }, {
    "type" : "WEB",
    "url" : "https://laravel.com/docs/12.x/reverb#scaling"
  }, {
    "type" : "WEB",
    "url" : "https://laravel.com/docs/reverb#scaling"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-502" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-21T15:40:24Z",
    "nvd_published_at" : "2026-01-21T22:15:50Z"
  }
}