Loading vulnerability…
CVE-2026-73316 is a payment replay vulnerability in XenForo versions before 2.3.13 affecting the PayPal REST payment provider. The provider does not check whether a transaction ID has already been processed. An attacker can therefore submit a valid PayPal webhook payload repeatedly, causing XenForo to process the same payment transaction as multiple payment events.
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
If you can’t patch tonight, do this now.
Patch, then assume compromise.
1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This is a small standalone Python proof of concept for CVE-2026-73316, a webhook replay flaw in XenForo versions before 2.3.13. The repository contains a README, a Python entry-point script (poc.py), and .gitignore rules that exclude the sensitive captured headers.json and callback.json input files. poc.py accepts a target base URL plus a JSON header file and raw callback body, appends /payment_callback.php?_xfProvider=paypalrest, and submits the exact same POST request twice with a 15-second timeout. It prints each response status and considers the target vulnerable if both are HTTP 200. The code is an active exploitation PoC rather than a detection-only script: a successful replay can cause duplicate purchase-completion processing. It requires an already authentic webhook and explicitly does not provide signature forgery or arbitrary webhook creation.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A payment-webhook replay vulnerability in XenForo versions before 2.3.13's PayPal REST payment provider. Missing duplicate transaction-ID validation permits replay of a valid webhook payload, causing duplicate payment events, repeated subscription activation, and unauthorized account upgrades.
A network-exploitable payment replay flaw in XenForo versions before 2.3.13's PayPal REST payment provider. Replaying an otherwise valid webhook can produce duplicate payment events, leading to repeated subscription activations and unauthorized account upgrades.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.