CVE-2026-73316
XenForo < 2.3.13 Payment Replay via PayPal REST Payment Provider
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
XenForo before 2.3.13 contains a payment replay vulnerability in the PayPal REST payment provider that allows attackers to process the same webhook payload multiple times by exploiting a missing duplicate transaction ID check. Attackers can replay a valid webhook payload to trigger duplicate payment events, resulting in repeated subscription activations and unauthorized account upgrades.
| CWE | CWE-345 |
| Vendor | xenforo |
| Product | xenforo |
| Published | Sep 8, 2026 |
| Last Updated | Sep 10, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Affected Versions
XenForo / XenForo
0 < 2.3.13
References
xenforo.com: https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/ xenforo.com: https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/ bombobombone.github.io: https://bombobombone.github.io/posts/cve-2026-73316/ github.com: https://github.com/BomboBombone/CVE-2026-73316 vulncheck.com: https://www.vulncheck.com/advisories/xenforo-payment-replay-via-paypal-rest-payment-provider
Credits
Marco Paciaroni (BomboBombone) VulnCheck