9.1

CVE-2026-11964: unknown user registration & membership Improper Authentication

CVSS: 9.1v3.1CriticalDeferred
Published 13-07-2026Last modified 13-07-2026
Open JSON

Vulnerability summary

CVE-2026-11964 is a critical (CVSS 9.1) Improper Authentication vulnerability in unknown user registration & membership. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 37.9% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 5.2.2.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.45%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Timeline

  1. 13-07-2026
    PublishedVulnerability first disclosed.
  2. 13-07-2026
    Last modifiedVulnerability information updated.

Description

The User Registration & Membership WordPress plugin before 5.2.2 does not verify the authenticity of incoming payment-provider webhook notifications before acting on them, allowing unauthenticated attackers to forge a payment-approved event and activate a paid membership subscription without completing a real payment.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.45%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

0.00 pp

From 0.45% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.45%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (wpscan.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Unknown1 product
Wordpress1 product
  • user-registration≤ 5.2.1 (fixed in 5.2.2)

2 vendors · 2 products

References

2 links