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.
Published: 2026-09-14
Score: 7.4 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

Mon, 14 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
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.
Title pay-rails/pay: non-constant-time HMAC comparison in Paddle Billing webhook signature verifier
Weaknesses CWE-208
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-14T18:57:30.947Z

Reserved: 2026-08-04T21:48:08.613Z

Link: CVE-2026-70658

cve-icon Vulnrichment

Updated: 2026-09-14T18:57:05.417Z

cve-icon NVD

Status : Received

Published: 2026-09-14T18:19:45.213

Modified: 2026-09-14T19:17:40.293

Link: CVE-2026-70658

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-208

    Observable Timing Discrepancy