TI-2026-86533 Aliases CVE-2026-93766 GHSA-4jjw-8w4r-774r

Stored cross-site scripting in Happyforms Pro WordPress plugin

LOW 29CWE-79Published 2026-11-07 · Updated 2026-11-07

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Cross-site scripting
Confidentiality · integrity · availability: Low · Low · None
Fix status: No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

The Happyforms Pro plugin for WordPress, all versions up to and including 1.38.9, does not sanitize input or escape output for the 'happyforms_client_referer' parameter, which is a stored cross-site scripting flaw (CWE-79). An unauthenticated attacker can inject arbitrary web scripts into pages that run in the browser of any user who opens an injected page.

Written with Claude Haiku 5.5 from the sources below · 2026-11-07

Description from the CNA

The Happyforms Pro plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'happyforms_client_referer' parameter in all versions up to, and including, 1.38.9 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Happyforms	Happyforms Pro	up to 1.38.9	—	No fix listed	CNA

Happyforms Pro VendorHappyforms Affected up to 1.38.9 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for Happyforms Pro.

Written with Claude Haiku 5.5 from the sources below · 2026-11-07

Timeline

2026-11-07 Threatist record created from CVE-2026-93766
2026-11-07 Alias added: GHSA-4jjw-8w4r-774r
2026-11-07 CISA SSVC decision points changed
2026-11-07 Priority changed: MEDIUM → LOW

References

Other 3

TI-2023-00092 Happyforms < 1.22.0 - Contributor+ Stored XSS CVSS 3.1MEDIUM 5.4
TI-2024-09328 Happyforms < 1.26.3 - Admin+ Stored XSS CVSS 3.1MEDIUM 4.8
TI-2026-36677 WordPress Happyforms plugin <= 1.26.13 - PHP Object Injection vulnerability CVSS 3.1CRITICAL 9.8
TI-2025-10981 HappyForms <= 1.26.12 - Authenticated (Admin+) Local File Inclusion CVSS 3.1MEDIUM 6.6
TI-2023-26582 WordPress Happyforms Plugin <= 1.25.9 is vulnerable to Cross Site Scripting (XSS) CVSS 3.1HIGH 7.1
TI-2026-63940 WordPress Happyforms plugin <= 1.26.15 - Cross Site Scripting (XSS) vulnerability CVSS 3.1HIGH 7.1

See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences