CVE-2026-23524: Laravel Redis Horizontal Scaling Insecure Deserialization
Impact
This vulnerability affects Laravel Reverb versions prior to v1.7.0 when horizontal scaling is enabled (REVERBSCALINGENABLED=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 REVERBSCALINGENABLED=false to bypass the vulnerable logic entirely.
Credits This vulnerability was discovered and responsibly reported by Mohammad Yaser Abo-Elmaaty @m0h4mmad
Other sources
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 (REVERBSCALINGENABLED=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 REVERBSCALINGENABLED=false to bypass the vulnerable logic entirely (if the environment uses only one Reverb node).
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-23524?
CVE-2026-23524 is considered a high severity vulnerability due to its potential for unauthorized data access through insecure deserialization.
How do I fix CVE-2026-23524?
To remediate CVE-2026-23524, upgrade the Laravel Reverb package to version 1.7.0 or higher.
What versions are affected by CVE-2026-23524?
CVE-2026-23524 affects all Laravel Reverb versions prior to 1.7.0 when horizontal scaling is enabled.
What should I do if I cannot upgrade for CVE-2026-23524?
If unable to upgrade for CVE-2026-23524, consider disabling horizontal scaling as a temporary mitigation strategy.
Can CVE-2026-23524 lead to data breaches?
Yes, CVE-2026-23524 can lead to data breaches by allowing attackers to exploit insecure deserialization vulnerabilities.