Happyforms Pro Stored Cross-Site Scripting via Spoofable Client IP Headers
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
Happyforms Pro for WordPress, in versions up to and including 1.38.9, contains a stored cross-site scripting flaw. The happyforms_get_client_ip() function trusts the spoofable HTTP_CLIENT_IP and HTTP_X_FORWARDED_FOR headers without validation and saves the value as post meta during form submissions, and the admin submission screen prints it without escaping (CWE-79). An unauthenticated attacker can inject arbitrary web scripts that run when an administrator opens the injected submission page.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
Description from the CNA
The Happyforms plugin for WordPress is vulnerable to Stored Cross-Site Scripting via spoofable client IP headers in versions up to, and including, 1.38.9. This is due to the happyforms_get_client_ip() function reading raw HTTP_CLIENT_IP and HTTP_X_FORWARDED_FOR request headers without any validation or sanitization, storing the value as post meta ('client_ip') via update_post_meta() during unauthenticated form submissions, and later echoing it in the admin submission edit screen's Details metabox without output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user (typically an administrator reviewing a submission) accesses an injected page.
Why it matters now
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-2026-93755
- 2026-11-07 Alias added: GHSA-4vjj-g4g8-7pwg
- 2026-11-07 CISA SSVC decision points changed
- 2026-11-07 Priority changed: MEDIUM → LOW
References
More Happyforms vulnerabilities
- 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
Sources
- CVE-2026-93755 · CVE Program
- CVE-2026-93755 · NVD
- GHSA-4vjj-g4g8-7pwg · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences