CVE-2021-36821Network attack vector

Unauthenticated stored XSS via unsanitized parameters

Published Mar 16, 2023 · Updated Apr 28, 2026

Stored XSS in WPMU DEV Forminator 1.14.11 and earlier allows remote attackers to inject scripts through unauthenticated requests. Public advisories do not name the affected parameters or code path; they state that some request parameters are stored without adequate sanitization and later rendered without escaping. Successful exploitation requires a privileged user action, after which the stored payload executes in that user's browser context and can alter displayed content or access page data.

CVSS severity7.1
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in WPMU DEV Forminator 1.14.11 and earlier allows remote attackers to inject scripts through unauthenticated requests. Public advisories do not name the affected parameters or code path; they state that some request parameters are stored without adequate sanitization and later rendered without escaping. Successful exploitation requires a privileged user action, after which the stored payload executes in that user's browser context and can alter displayed content or access page data.

The record

CVE
CVE-2021-36821
Published
Mar 16, 2023
Updated
Apr 28, 2026
Vendor
WPMU DEV
Product
Forminator
Classifications
CWE-79, CAPEC-592, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=1.14.11
  2. Affected versionversion=n/a <=1.14.11 changes=[{"at":"1.14.12","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WPMU DEV · Forminatorversion=0 <=1.14.11; version=n/a <=1.14.11 changes=[{"at":"1.14.12","status":"unaffected"}]

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
7.1PatchstackCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-592Stored XSS
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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