CVE-2026-73314

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-08. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
39%
KEV
Not listed

Published

September 8, 2026

Last Modified

September 11, 2026

Advisory Details (1)

Auto-updated Sep 8, 2026
No patch confirmed yet.
generic

XenForo < 2.3.13 Signature Verification Bypass via PayPal REST Webhook | Advisories | VulnCheck

https://www.vulncheck.com/advisories/xenforo-signature-verification-bypass-via-paypal-rest-webhook

Vendor Advisories for CVE-2026-73314(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 25× in last 7d / 53× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-19 21:56 UTCEG score recompute
  2. 2026-09-19 21:56 UTCGHSA enrichment
  3. 2026-09-19 09:54 UTCGHSA enrichment
  4. 2026-09-18 21:25 UTCEG score recompute
  5. 2026-09-18 21:25 UTCGHSA enrichment
  6. 2026-09-18 19:28 UTCEPSS rescore
  7. 2026-09-18 09:24 UTCGHSA enrichment
  8. 2026-09-17 21:22 UTCEG score recompute
  9. 2026-09-17 21:22 UTCGHSA enrichment
  10. 2026-09-17 09:20 UTCGHSA enrichment
  11. 2026-09-16 21:18 UTCEG score recompute
  12. 2026-09-16 21:18 UTCGHSA enrichment
  13. 2026-09-16 14:08 UTCEPSS rescore
  14. 2026-09-16 09:16 UTCEG score recompute
  15. 2026-09-16 09:16 UTCGHSA enrichment
  16. 2026-09-16 05:15 UTCEPSS rescore
  17. 2026-09-15 21:14 UTCGHSA enrichment
  18. 2026-09-15 09:12 UTCEG score recompute
  19. 2026-09-15 09:12 UTCGHSA enrichment
  20. 2026-09-15 03:12 UTCEPSS rescore
  21. 2026-09-14 21:10 UTCGHSA enrichment
  22. 2026-09-14 08:54 UTCGHSA enrichment
  23. 2026-09-13 20:53 UTCEG score recompute
  24. 2026-09-13 20:53 UTCGHSA enrichment
  25. 2026-09-13 08:51 UTCGHSA enrichment
Show 28 more
  1. 2026-09-12 20:50 UTCEG score recompute
  2. 2026-09-12 20:50 UTCGHSA enrichment
  3. 2026-09-12 15:02 UTCEPSS rescore
  4. 2026-09-12 08:49 UTCGHSA enrichment
  5. 2026-09-11 20:47 UTCEG score recompute
  6. 2026-09-11 20:47 UTCGHSA enrichment
  7. 2026-09-11 14:53 UTCEPSS rescore
  8. 2026-09-11 14:25 UTCEG score recompute
  9. 2026-09-11 14:25 UTCGHSA enrichment
  10. 2026-09-11 02:24 UTCEG score recompute
  11. 2026-09-11 02:24 UTCGHSA enrichment
  12. 2026-09-10 14:22 UTCEG score recompute
  13. 2026-09-10 14:22 UTCGHSA enrichment
  14. 2026-09-10 13:50 UTCEG score recompute
  15. 2026-09-10 13:50 UTCGHSA enrichment
  16. 2026-09-10 13:26 UTCEG score recompute
  17. 2026-09-10 13:26 UTCGHSA enrichment
  18. 2026-09-10 09:35 UTCEPSS rescore
  19. 2026-09-10 01:24 UTCGHSA enrichment
  20. 2026-09-09 13:23 UTCEG score recompute
  21. 2026-09-09 13:23 UTCGHSA enrichment
  22. 2026-09-09 01:18 UTCEG score recompute
  23. 2026-09-09 01:18 UTCGHSA enrichment
  24. 2026-09-08 20:12 UTCEG score recompute
  25. 2026-09-08 20:12 UTCGHSA enrichment
  26. 2026-09-08 14:30 UTCEG score recompute
  27. 2026-09-08 13:26 UTCEG score recompute
  28. 2026-09-08 13:24 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-73314?
CVE-2026-73314 is a high vulnerability published on September 8, 2026. 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…
When was CVE-2026-73314 disclosed?
CVE-2026-73314 was first published in the National Vulnerability Database on September 8, 2026, with the most recent update on September 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73314 actively exploited?
CVE-2026-73314 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 61.4% of all scored CVEs.
What is the CVSS score of CVE-2026-73314?
CVE-2026-73314 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-73314?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-73314, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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