# CVE-2026-70658

## Summary

- **CVE ID:** CVE-2026-70658
- **Severity:** HIGH
- **CVSS Score:** 7.4 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)
- **CWE:** CWE-208
- **Published:** Sep 14, 2026
- **Last Modified:** Sep 14, 2026

## Description

Pay is a payments engine for Ruby on Rails 6.0 and higher. Prior to 11.6.2, Pay::Webhooks::PaddleBillingController#valid_signature? in app/controllers/pay/webhooks/paddle_billing_controller.rb compares the computed 64-character SHA-256 HMAC with the attacker-controlled h1 token from the Paddle-Signature header using Ruby String#==. An unauthenticated remote attacker who can repeatedly submit requests to /pay/webhooks/paddle_billing and obtain sufficiently precise timing measurements can infer matching digest prefixes and recover a valid signature. A forged accepted webhook is enqueued through Pay::Webhooks::ProcessJob and can cause a host application to update billing state, provision paid features, record refunds, or trigger customer notifications. This issue is fixed in version 11.6.2.

## Affected Products

- pay-rails — pay (< 11.6.2)

## References

- [CNA](https://github.com/pay-rails/pay/security/advisories/GHSA-mjgf-xj26-9qf9)
- [CNA](https://github.com/pay-rails/pay/commit/ba6494109d88209fba2a4df2d9d6373fe81ed805)
- [CNA](https://github.com/pay-rails/pay/releases/tag/v11.6.2)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.50%
- **EPSS Percentile:** 41.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._