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SimpleForm EUVDEUVD-2026-114672

| CVE-2026-118235 CRITICAL
Unrestricted Upload of File with Dangerous Type (CWE-434)
2026-10-31 Wordfence GHSA-wjww-5gvr-r96j
9.8
CVSS 3.1 · Vendor: Wordfence
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Visit page embedding form shortcode
  2. Delivery
    Read nonce from data-nonce attribute
  3. Exploit
    Submit crafted trailing-dot filename to handle_upload
  4. Execution
    Bypass extension/MIME validation
  5. Persist
    Upload executable file
  6. Impact
    Request uploaded file for RCE

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V5 - File Handling File type validation, storage isolation
MITRE ATT&CK

2 techniques across 2 tactics: Command and Control, Persistence

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

No special conditions beyond the plugin being installed and at least one public page embedding the SimpleForm form shortcode (which exposes the data-nonce value that gates handle_upload). The exploit requires sending a file with a trailing-dot filename to the handle_upload function, which lacks a server-side file key allowlist and derives the extension before sanitization, bypassing all extension and MIME checks. The practical limiting factors are: the plugin (versions up to and including 3.10.2) must be installed and active, and a form must be embedded somewhere publicly reachable so the nonce is obtainable; successful RCE additionally requires that the upload destination permits execution of the uploaded file type by the web server. No authentication, no privileged account, and no user interaction are required.

Impact

This is a genuine top-priority vulnerability, and the signals are internally consistent rather than conflicting. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, 9.8) describes fully remote, low-complexity, unauthenticated exploitation with high confidentiality, integrity, and availability impact, and the description substantiates each of those metrics: the only access control is a nonce that the plugin itself prints into every public form's data-nonce attribute, so the PR:N (unauthenticated) metric is not merely formal - the nonce is trivially harvestable by any visitor, meaning there is effectively no authentication barrier. The CWE-434 arbitrary file upload leading to RCE matches the C:H/I:H/A:H impact. The vuln.today decision label is act_now, and the finding was reported by Wordfence, a credible WordPress-vulnerability source. The main caveat is that no EPSS score and no KEV listing were provided in the input, and no confirmed working exploit code is referenced; therefore active, widespread exploitation is NOT demonstrated by the available data. In short: this is a real, high-urgency issue driven by an unauthenticated-RCE mechanism and an act_now decision label, not a high-CVSS-but-low-real-risk case - but the urgency rests on the severity and ease of exploitation, not on evidence of in-the-wild attacks, which the input does not establish.

Exploit ScenarioDerived

An unauthenticated attacker visits any public page that embeds the SimpleForm shortcode, reads the nonce from the form's data-nonce attribute, and submits the handle_upload endpoint a malicious file whose name ends in a trailing dot (e.g. shell.php.), which bypasses the extension and MIME validation. The uploaded executable file is then requested directly to achieve remote code execution. No public exploit code is identified in the provided data, though the vulnerable source lines are publicly browsable on the WordPress plugin trac.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.7% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 31, 2026

Unauthenticated arbitrary file upload in the SimpleForm WordPress plugin through 3.10.2 lets remote attackers write files that may be executable by the web server, with remote code execution possible where the upload directory permits script execution. The handle_upload function derives the file extension before sanitization and lacks a server-side file-key allowlist, so a trailing-dot filename bypasses extension and MIME checks; the only gate is a nonce exposed in every public form's data-nonce attribute. No public exploit is identified in the provided data, but the vendor-reported severity is critical (CVSS 9.8) and the priority label is act_now.

RemediationAI

No tagged fixed release is identified in the supplied data; the trunk changeset at https://plugins.trac.wordpress.org/changeset/3770697/simple-form/trunk/app/FileUpload.php modifies app/FileUpload.php. Apply the vendor update once a release containing that changeset is available and confirm the installed version is later than 3.10.2. If an update cannot be applied immediately, deactivate the SimpleForm plugin, because the upload endpoint is reachable from any public page embedding the form shortcode and the required nonce is disclosed there. Advisory: https://www.wordfence.com/threat-intel/vulnerabilities/id/6aac2178-f6ce-4444-9afc-7e014547cd48?source=cve.

Affected VersionsENISA

SimpleForm – Form Maker to Chat Apps with Quiz, Poll and Multi Lead Notifications 0 ≤3.10.2

Affected Packages

euvd simpleform_form_maker_to_chat_apps_with_quiz_poll_and_multi_lead_notifications no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The issue is CWE-434 (Unrestricted Upload of File with Dangerous Type) in the WordPress plugin SimpleForm - Form Maker to Chat Apps with Quiz, Poll and Multi Lead Notifications. The vulnerable path is the handle_upload function in app/FileUpload.php (referenced lines 118, 137, and 142), with related AJAX handling in app/Ajax/Tables.php (lines 67, 973, and 988) that exposes the nonce used as the only access control. Because the extension is derived before sanitization and no server-side allowlist of file keys is enforced, a filename with a trailing dot bypasses both extension and MIME validation, allowing a file that may be executable to be written. The nonce is printed into the data-nonce attribute of every public form, so any unauthenticated visitor on a page embedding the form shortcode can obtain it. Successful remote code execution additionally depends on the upload destination permitting execution of the uploaded file type by the web server.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (Wordfence) PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 9.8 CRITICAL

Unauthenticated (the gating nonce is public), remote, and low-complexity trailing-dot bypass yielding file upload and RCE, so PR:N/AC:L and C/I/A all High.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (Wordfence).

CVSS VectorVendor: Wordfence

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

The SimpleForm - Form Maker to Chat Apps with Quiz, Poll and Multi Lead Notifications plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 3.10.2 via the handle_upload function. This is due to missing server-side file key allowlist and pre-sanitization extension derivation that allows a trailing-dot filename to bypass all extension and MIME validation in handle_upload. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible. The only access control is a nonce that is printed into every public form's data-nonce attribute, making it trivially obtainable by any unauthenticated visitor on a page embedding the form shortcode.

Executive ViewAI

Why It Matters

The SimpleForm WordPress plugin (versions up to 3.10.2) contains a critical unauthenticated file upload vulnerability that could allow attackers to execute arbitrary code on affected web servers. This puts all WordPress sites using this plugin at risk of full compromise, potentially leading to data breaches, site defacement, or use as a pivot point for further attacks.

Business Impact: High
Compensating Controls

Disable the plugin, restrict file upload directories from executing scripts, deploy WAF rules to detect and block malicious uploads, and monitor for indicators of compromise.

Threat Intelligence Overview

EPSS Score
0.7%
Top 45% exploitable
Prevalence
Low
specific third-party WordPress form plugin, modest install base
Social Media
5
Sightings
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.7%
Patch available No
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
High
Technical Impact
Total

Priority Score

50
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +49
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Malicious file upload attacks exploit insufficient validation when web applications accept user-provided files.

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

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