CVE-2026-73316CWE-345

CVE-2026-73316

High · published September 8, 2026

CVSS v3.1

7.5

EPSS

Percentile

17.4

In the wild

Unconfirmed

What it is

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.

The record

Technical detail

CVSS v3.1: 7.5 · HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS v4.0: 8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS: 0.00265 · 17.4th percentile
Weakness: CWE-345 · Insufficient Verification of Data Authenticity
Published: 2026-09-08T18:17Z

Affected products (1)

Product	Versions	Fixed in
xenforo/xenforo	< 2.3.13	2.3.13

References (5)

https://bombobombone.github.io/posts/cve-2026-73316/ · [email protected]https://github.com/BomboBombone/CVE-2026-73316 · [email protected]https://www.vulncheck.com/advisories/xenforo-payment-replay-via-paypal-rest-payment-provider · [email protected]https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/ · [email protected]https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/ · [email protected]

EPSS history

Timeline

10 SEP 03:18Z
EPSS moved — → 0%
epss
08 SEP 13:18Z
XenForo < 2.3.13 Payment Replay via PayPal REST Payment Provider
cvelistv5