CVE-2026-70658

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.

CVSS 3.1

7.4CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

0.6% chance of exploitation in the next 30 days; higher than 47% of CVEs (scores of 2026-10-25)

CWE

CWE-208

Published

2026-09-14

Modified

2026-09-30

Record from

the NVD, synced 2026-10-19

Packages (OSV)

References

• https://github.com/pay-rails/pay/commit/ba6494109d88209fba2a4df2d9d6373fe81ed805
• https://github.com/pay-rails/pay/releases/tag/v11.6.2
• https://github.com/pay-rails/pay/security/advisories/GHSA-mjgf-xj26-9qf9
• https://github.com/pay-rails/pay/security/advisories/GHSA-mjgf-xj26-9qf9

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