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TI-2026-51440 Aliases CVE-2026-73315GHSA-x4fx-w4wf-c38c

XenForo < 2.3.13 SSRF via PayPal REST Webhook Handler

Priority MEDIUM 40CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

XenForo before 2.3.13 contains a server-side request forgery vulnerability in the PayPal REST webhook handler that allows unauthenticated attackers to cause the server to make outbound HTTP requests to arbitrary destinations by supplying a crafted certificate URL in webhook headers without scheme, hostname, or allowlist validation. Attackers can submit a crafted POST to the PayPal webhook callback endpoint to reach internal network resources including cloud instance metadata services, potentially disclosing IAM credentials or enabling secondary internal service exploitation.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00357 29th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD and the CNA
Fix Fixed XenForo (XenForo): 2.3.13

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
XenForoXenForobefore 2.3.132.3.13Patch availableCNA
  • XenForo VendorXenForo Affected before 2.3.13 Fixed in 2.3.13 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:xenforo:xenforo:*:*:*:*:*:*:*:*before 2.3.13VulnerableXenForo
  • cpe:2.3:a:xenforo:xenforo:*:*:*:*:*:*:*:* Versions before 2.3.13 Vulnerable ·XenForo

Remediation

  • Fix · CNA XenForo (XenForo) Fixed in 2.3.13

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    XenForo — xenforo.com/community/threads/security-fixes-released-for-a…

    14 records Highest priority Priority HIGH 4 HIGH, 5 MEDIUM, 5 LOW

    Other records, highest priority first

    • TI-2026-51441 XenForo < 2.3.13 Payment Replay via PayPal REST Payment ProviderPriority HIGH 77
    • TI-2026-51439 XenForo < 2.3.13 Signature Verification Bypass via PayPal REST WebhookPriority HIGH 77
    • TI-2026-51436 XenForo < 2.3.13 OAuth2 Authorization Code ReusePriority HIGH 74
    Show all 14 records → Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-73315
  2. 2026-10-03 Alias added: GHSA-x4fx-w4wf-c38c

References

Exploit 2

Patch 1

Other 1

  • TI-2026-51441 XenForo < 2.3.13 Payment Replay via PayPal REST Payment Provider CVSS 4.0HIGH 8.7
  • TI-2026-51439 XenForo < 2.3.13 Signature Verification Bypass via PayPal REST Webhook CVSS 4.0HIGH 8.7
  • TI-2026-51436 XenForo < 2.3.13 OAuth2 Authorization Code Reuse CVSS 4.0CRITICAL 9.1
  • TI-2026-51434 XenForo < 2.3.13 Authentication Bypass via OAuth2 Token Endpoint CVSS 4.0CRITICAL 9.1
  • TI-2024-25701 Xenforo before 2.2.16 allows code injection. CVSS 3.1HIGH 8.8
  • TI-2026-51446 XenForo < 2.3.13 Uncontrolled Recursion DoS via BBCode Parser CVSS 4.0HIGH 7.1
See all 27 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences