CVE-2023-0096Public exploitNetwork attack vector

Stored XSS via unescaped Gutenberg block attribute

Published Feb 6, 2023 · Updated Mar 25, 2025

Stored XSS in Happyforms before 1.22.0 allows remote authenticated users to execute JavaScript via a crafted Gutenberg block attribute. The Forms block outputs its Additional CSS class value into page markup without escaping injected quotes and event-handler syntax. Contributor access is required to save the payload, and code runs when another user interacts with the embedded block.

CVSS severity5.4
Medium
EPSS probability0.50%
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 Happyforms before 1.22.0 allows remote authenticated users to execute JavaScript via a crafted Gutenberg block attribute. The Forms block outputs its Additional CSS class value into page markup without escaping injected quotes and event-handler syntax. Contributor access is required to save the payload, and code runs when another user interacts with the embedded block.

The record

CVE
CVE-2023-0096
Published
Feb 6, 2023
Updated
Mar 25, 2025
Vendor
The Theme Foundry
Product
Happyforms
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 6, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 25, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <1.22.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Theme Foundry · Happyformsversion=0 <1.22.0

Published CVSS scores

5.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

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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