8.8

CVE-2026-11855: unknown simple membership Cross-site Scripting

CVSS: 8.8v3.1HighDeferred
Published 06-07-2026Last modified 06-07-2026
Open JSON

Vulnerability summary

CVE-2026-11855 is a high (CVSS 8.8) Cross-site Scripting vulnerability in unknown simple membership. EPSS estimates a 0.51% chance of exploitation in the next 30 days, higher than 41.8% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 4.7.5.

Overall risk
45/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.51%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Timeline

  1. 06-07-2026
    PublishedVulnerability first disclosed.
  2. 06-07-2026
    Last modifiedVulnerability information updated.

Description

The Simple Membership WordPress plugin before 4.7.5 does not verify the authenticity of Stripe webhook requests when no signing secret is configured, nor escape a value taken from them before outputting it in an administrator notice, allowing unauthenticated attackers to inject arbitrary web scripts that execute in the context of a logged-in administrator.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.51%

Chance of exploitation in the next 30 days

Percentile

42%

Versus all other CVEs

30-day change

0.00 pp

From 0.51% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.51%

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
  • simple-membership≤ 4.7.4 (fixed in 4.7.5)

2 vendors · 2 products

References

2 links