Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| XenForo | XenForo | < 2.3.13 | 2.3.13 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
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BomboBombone/CVE-2026-73316 ★ 0 · Sep 8, 2026
Sanitized XenForo write-up and proof of concept for CVE-2026-73316.
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
References
- Vendor Advisory vendor-advisory patch
- Release Notes release-notes
- Researcher Advisory technical-description
- Researcher PoC exploit
- https://www.vulncheck.com/advisories/xenforo-payment-replay-via-paypal-rest-payment-provider third-party-advisory