Laravel Redis Horizontal Scaling Insecure Deserialization

CRITICAL 9.8CVE-2026-23524 · GHSA-m27r-m6rx-mhm4 · Published 21/01/2026 · updated 17/06/2026

Package	Affected versions	Patched versions
laravel/reverb Packagist	`< 1.7.0`	`1.7.0`
reverb laravel	`< 1.7.0`	`1.7.0`

Description

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

NVD description

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).

References

laravel/reverb security advisory · WEB
nvd.nist.gov/vuln/detail/CVE-2026-23524 · ADVISORY
laravel/reverb commit 9ec26f8 · WEB
laravel/reverb · PACKAGE
laravel/reverb release v1.7.0 · WEB
laravel.com/docs/12.x/reverb · WEB
laravel.com/docs/reverb · WEB
cwe.mitre.org/data/definitions/502.html · Technical Description

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Package

Affected versions

Patched versions

laravel/reverb

Packagist

< 1.7.0

1.7.0

reverb

laravel

< 1.7.0

1.7.0

Description

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.

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

NVD description