Threat intelligence

Formidable Forms <= 6.33.1 - Unauthenticated Stored Cross-Site Scripting via 'frm_user_id' Parameter

CVE-2026-18331 · formidable

Important: Seeing this vulnerability listed does not mean your website is affected. Exposure depends on whether you run Formidable at a vulnerable version. How SiteRespond intelligence works

Vulnerability: Formidable Forms <= 6.33.1 - Unauthenticated Stored Cross-Site Scripting via 'frm_user_id' Parameter
Affected software: formidable(Plugin)
Affected versions: ≤ 6.33.1
Authentication: Unauthenticated
Vulnerability type: Cross-site scripting
CVE: CVE-2026-18331
Published: 25 August 2026
CISA KEV: Not listed in CISA KEV at last catalog refresh
Impact: May allow attackers to run scripts in visitors' browsers or hijack admin sessions.
Source: Data imported from Wordfence Intelligence (advisory f03b09ad-257c-48c9-8ecc-36f60f178f80). Methodology and redistribution notes

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