GHSA-pfrr-xvrf-pxjx
Laravel Reverb Missing API Signature Verification
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
laravel/reverbReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A community member disclosed an issue where verification signatures for requests sent to Reverb's Pusher-compatible API were not being verified. This API is used in scenarios such as broadcasting a message from a backend service or for obtaining statistical information (such as number of connections) about a given channel.
The verification signature is a hash comprised of different parts of the request signed by the app's secret key. The signature is sent as part of the request and should be regenerated by Reverb. Only when both the signature in the request and the one generated by Reverb match should the request be allowed. This helps to verify the request came from a known source.
[!NOTE]
This issue only affects the Pusher-compatible API endpoints and not the WebSocket connections themselves. In order to exploit this vulnerability, the application ID which, should never be exposed, would need to be known by an attacker.
The following endpoints were affected:
POST /events
POST /events_batch
GET /connections
GET /channels
GET /channel
GET /channel_users
POST /users_terminate
Patches
The issue was resolved by #252 and the patch released in v1.4.0.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | laravel/reverb | all versions | 1.4.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for laravel/reverb. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update laravel/reverb to 1.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pfrr-xvrf-pxjx is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-pfrr-xvrf-pxjx is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-pfrr-xvrf-pxjx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-pfrr-xvrf-pxjx in your dependencies?
O3 detects GHSA-pfrr-xvrf-pxjx across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.