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UltimateAI EUVDEUVD-2026-65164

| CVE-2026-32559 CRITICAL
Unrestricted Upload of File with Dangerous Type (CWE-434)
2026-08-24 Patchstack GHSA-vjvh-rjh6-h3qf
9.9
CVSS 3.1 · Vendor: Patchstack
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Attack ChainAIDerived

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

  1. Access
    Obtain Subscriber account (register or login)
  2. Delivery
    Reach UltimateAI upload endpoint
  3. Exploit
    Upload PHP file bypassing type checks
  4. Execution
    Request uploaded shell URL
  5. Persist
    Execute code as web server
  6. Impact
    Full WordPress site takeover

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

Exploitation requires an authenticated WordPress account at Subscriber level or higher (CVSS PR:L) that can reach the UltimateAI plugin's file-upload feature; the plugin (≤ 3.1.0) must be installed and active. The key limiting factor is obtaining that account: on sites where self-registration is enabled the barrier is negligible, while sites with registration disabled require the attacker to already hold or phish valid low-tier credentials. No user interaction, no admin privileges, and no non-default plugin configuration are needed beyond the plugin being present and the account being able to access the vulnerable upload endpoint.

Impact

The signals point to a genuine high priority for exposed WordPress sites, but with an important gate. The CVSS 3.1 vector AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H yields 9.9 (Critical): network-reachable, low complexity, no user interaction, and full confidentiality/integrity/availability impact with scope change. The one mitigating factor is PR:L - exploitation requires an authenticated account, specifically Subscriber level. On WordPress sites that allow open user self-registration (a common default for membership/comment features), that barrier is trivially met, making this effectively remotely exploitable; on sites with registration disabled, an attacker first needs valid low-tier credentials. EPSS probability is not provided in the input, and there is no KEV listing and no known public POC, so there is no evidence of active or automated exploitation yet - the risk is currently potential rather than observed. Arbitrary-file-upload flaws in WordPress plugins are, however, a favored target for mass opportunistic scanning once a POC appears, so patch urgency should be treated as high despite the missing EPSS/KEV data.

Exploit ScenarioDerived

An attacker registers (or logs into) a low-privileged Subscriber account on a target WordPress site running UltimateAI ≤ 3.1.0, then sends a crafted request to the plugin's unvalidated upload handler containing a PHP web shell. The file lands in a web-accessible directory, and the attacker requests its URL to execute arbitrary code as the web server user, achieving full site takeover. No user interaction is required and attack complexity is low; no public POC is currently identified.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 24, 2026

Arbitrary file upload in the UltimateAI WordPress plugin (versions up to and including 3.1.0) lets any authenticated Subscriber-level user upload files with attacker-controlled types, per Patchstack (CVE-2026-32559, CWE-434). Because the plugin fails to validate uploaded file types, a low-privileged account can place a malicious PHP payload on the server, and with a CVSS 3.1 base score of 9.9 and scope change this typically escalates to full remote code execution and site takeover. No public exploit identified at time of analysis.

RemediationAI

Upgrade UltimateAI to a version later than 3.1.0 once the vendor publishes a patched release; the input data does not confirm an exact fixed version, so verify the current version against the Patchstack advisory (https://patchstack.com/database/wordpress/plugin/ultimate_ai/vulnerability/wordpress-ultimateai-plugin-3-1-0-arbitrary-file-upload-vulnerability?_s_id=cve) and the plugin changelog before relying on it. Because no fix version is independently confirmed here, apply compensating controls in the meantime: disable or deactivate the UltimateAI plugin if it is not essential; disable open user self-registration (set 'Anyone can register' off in WordPress settings) to remove the Subscriber prerequisite; place a WAF rule or Patchstack virtual patch in front of the plugin's upload endpoint; and harden the uploads directory by blocking PHP execution in wp-content/uploads (e.g. a .htaccess or nginx rule denying execution of .php files) so an uploaded payload cannot run even if written. Note trade-offs: deactivating the plugin removes its functionality, and disabling registration breaks any legitimate self-service signup workflow.

Affected VersionsENISA

UltimateAI n/a ≤3.1.0

Affected Packages

euvd ultimateai 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

UltimateAI is a WordPress plugin (vendor 'tophive', CPE cpe:2.3:a:tophive:ultimateai:*:*:*:*:*:*:*:*) that adds AI features to WordPress sites. The root cause is CWE-434 (Unrestricted Upload of File with Dangerous Type): an upload handler exposed to Subscriber-role users does not enforce an allow-list of safe extensions or MIME types, nor place uploads outside the web root. In a WordPress context, any script written into a web-served directory (e.g. wp-content/uploads) can be requested directly by URL and executed by the PHP interpreter, turning a file-write primitive into code execution. The CVSS scope change (S:C) reflects that the compromised plugin can affect the entire WordPress host beyond the plugin's own security authority.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (Patchstack) PRIMARY 9.9 CRITICAL
AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
vuln.today AI 9.9 CRITICAL

Network-reachable upload needing only a Subscriber account (PR:L), no interaction; unrestricted upload yields RCE with host-wide scope change (S:C) and full C/I/A loss.

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

Primary rating from Vendor (Patchstack).

CVSS VectorVendor: Patchstack

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

DescriptionCVE.org

Subscriber Arbitrary File Upload in UltimateAI <= 3.1.0 versions.

Executive ViewAI

Why It Matters

The UltimateAI WordPress plugin (versions through 3.1.0) exposes a critical file upload vulnerability allowing any low-privileged user account to upload and execute code on the server, leading to full website and infrastructure compromise. This directly affects any organization using this plugin and cannot be mitigated by standard WordPress security controls. No patch is currently available, requiring immediate operational response.

Business Impact: Severe
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: (1) Disable the plugin if non-essential; (2) If required operationally, restrict file uploads to Administrator accounts exclusively; (3) Configure web server to block execution of scripts (.php, .phtml, .php5) within plugin upload directories; (4) Deploy Web Application Firewall rules to block upload requests containing executable file signatures; (5) Enable comprehensive logging and alerting on all file upload attempts; (6) Conduct immediate filesystem scan of existing uploads for suspicious executable files.

Threat Intelligence Overview

EPSS Score
0.4%
Top 71% exploitable
Prevalence
Low
niche third-party WordPress AI plugin, limited install base
Data Quality
4 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 0.4%
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· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact
Very High

Priority Score

50
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +50
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.

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