CVE•Published 2026-09-08•Modified 2026-09-11•0 articles on news•5 live references•NVD data

CVE-2026-73314Xenforo · Xenforo

Vulnerability data via NVD (ingested)

CVSS v3.1

7.5

HIGH

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

EPSS percentile

Exploit Prediction Scoring System · top 62% of all CVEs

Weaknesses (CWE)

CWE-754Improper Check for Unusual or Exceptional Conditions

Description

XenForo before 2.3.13 contains a signature verification logic error in the PayPal REST webhook handler that allows unauthenticated attackers to bypass payment signature validation by submitting a webhook request with an unsupported auth_algo header value. When the algorithm cannot be mapped to a supported hash function, the verification function incorrectly returns true instead of failing, causing the caller to treat the fabricated request as verified and process the payment event without a valid PayPal signature.

Timeline

Published 2026-09-08

Modified 2026-09-11

External references

NVD MITRE Exploit-DB trickest/cve VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-73314

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Xenforo Xenforo"

All exposed Xenforo Xenforo instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Xenforo"

HTTP body or banner mentions "Xenforo" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-73314