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Critical

Unauthenticated PHP Code Injection RCE in Everest Forms Pro Complex Calculation

IdentifiersCVE-2026-3300CWE-94· Improper Control of Generation of…

CVE-2026-3300 is a critical remote code execution vulnerability in the Everest Forms Pro WordPress plugin affecting all versions up to and including 1.9.12. The flaw is in the Calculation Addon’s process_filter() function within the Complex Calculation feature, where user-supplied form field values are concatenated into a dynamically constructed PHP code string and then executed via eval(). Although input is passed through sanitize_text_field(), that function does not escape single quotes and other characters significant in PHP code context. As a result, an attacker can break out of the intended string context and inject arbitrary PHP code. Exploitation is possible through crafted submissions to string-type form fields such as text, email, URL, select, and radio fields on forms that use the Complex Calculation feature. The issue is exploitable without authentication and has been observed in active exploitation in the wild.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows unauthenticated attackers to execute arbitrary PHP code on the target server in the context of the WordPress application. This can result in full site compromise, including creation of rogue administrator accounts, upload of webshells, deployment of backdoors, modification of site content, access to or manipulation of local application data, and potential pivoting further into the hosting environment. Observed exploitation has commonly attempted to create unauthorized WordPress administrator accounts for persistence.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by disabling forms that use the Complex Calculation feature or disabling the Everest Forms Pro plugin until it can be updated. Monitor and filter requests to /wp-admin/admin-ajax.php for suspicious crafted POST submissions targeting Everest Forms functionality. Review WordPress user accounts for unauthorized administrators, especially known observed usernames such as "diksimarina," and inspect logs for requests from reported malicious IPs. Apply WAF protections where available.

Remediation

Patch, then assume compromise.

Upgrade Everest Forms Pro to version 1.9.13 or later, which contains the vendor’s fix for CVE-2026-3300. Because the vulnerability has been actively exploited, administrators should also perform post-upgrade incident response checks, including reviewing WordPress administrator accounts for unauthorized users, inspecting logs for exploitation attempts against /wp-admin/admin-ajax.php, and investigating for persistence mechanisms such as webshells or backdoors if compromise is suspected.
PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
WpeverestEverest Forms Proapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity21

Community discussion across Reddit, Mastodon, and other social sources.