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Kiteworks CVE-2026-23636

| EUVDEUVD-2026-15541 MEDIUM
Unrestricted Upload of File with Dangerous Type (CWE-434)
2026-03-25 GitHub_M
5.5
CVSS 3.1 · GitHub Advisory
View

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.

Impact

The CVSS v3.1 score of 5.5 (Medium severity) reflects a nuanced risk profile: the attack vector is network-based with low complexity, but requires high privileges (PR:H), reducing the overall severity. The integrity impact is high (I:H) while availability impact is low (A:L), indicating file corruption or injection is the primary concern rather than system-wide outage. However, this CVSS score should not be underestimated—CWE-434 vulnerabilities are historically dangerous and frequently lead to remote code execution when combined with web server misconfigurations (e.g., executable permissions in upload directories). Without confirmed EPSS data or KEV listing in this dataset, the real-world exploitability depends on whether uploaded files can be executed by the web server or accessed by other users. The requirement for manager-level authentication significantly reduces the attack surface, making this an insider threat or post-compromise lateral movement vector rather than a primary access mechanism. Organizations should prioritize patching but recognize this is lower risk than unauthenticated file upload vulnerabilities.

Exploit ScenarioDerived

A malicious insider with form manager credentials, or an external attacker who has compromised a manager account through phishing, could upload a web shell or executable script disguised with a dangerous file extension through the Secure Data Forms interface. If the upload directory is executable or if the file can be accessed via the web root, the attacker gains remote code execution with the privileges of the web server process, allowing them to exfiltrate sensitive data stored on the PDN, establish persistence, or pivot to internal systems. The attack requires low technical complexity and network access only (no special tools), making it a practical post-authentication attack vector.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 25, 2026

Kiteworks Secure Data Forms contains an unrestricted file upload vulnerability (CWE-434) that allows form managers to upload files with dangerous types due to missing input validation. An authenticated attacker with manager privileges can exploit this to upload malicious files, potentially leading to code execution or system compromise. The vulnerability affects all versions prior to 9.2.1, and a patch is available; no public exploit code has been confirmed, but the moderate CVSS score of 5.5 reflects the high integrity impact combined with the requirement for elevated privileges.

RemediationAI

Immediately upgrade Kiteworks to version 9.2.1 or later, which contains the patch for this vulnerability. The vendor has provided the fix in the official release, and deployment should be prioritized given the file upload nature of the flaw. Until patching is completed, implement compensating controls by restricting form manager access to trusted administrators only, disabling upload functionality if not critical, and ensuring the upload directory is not executable by the web server (verify file permissions and web server configuration to prevent execution of uploaded files). Monitor upload activity logs for suspicious file types or patterns. Organizations unable to immediately patch should contact Kiteworks support for guidance on temporary mitigations specific to their deployment.

Affected VersionsENISA

Secure Data Forms < 9.2.1

Affected Packages

euvd secure_data_forms fix: 9.2.1

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 vulnerability resides in Kiteworks Secure Data Forms, a component of the Kiteworks Private Data Network (PDN) platform designed to facilitate secure data exchange. The root cause is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type), a critical input validation flaw where the application fails to properly validate or restrict file types during upload operations. This validation gap exists in the form management functionality, specifically in code paths accessible to users with manager-level privileges. The lack of proper file type checking, MIME type validation, and execution prevention mechanisms allows dangerous file extensions or executable content to bypass security controls and be stored on the server.

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Severity by source

GitHub Advisory PRIMARY 5.5 MEDIUM
AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:L

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

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

Lifecycle Timeline

2
Patch available
Apr 16, 2026 - 05:29 EUVD
9.2.1
CVE Published
Mar 25, 2026 - 16:58 nvd
MEDIUM 5.5

DescriptionGitHub Advisory

Kiteworks is a private data network (PDN). In Kiteworks Secure Data Forms prior to version 9.2.1, the manager of a form could potentially exploit an Unrestricted Upload of File with Dangerous Type due to a missing validation. Upgrade Kiteworks to version 9.2.1 or later to receive a patch.

Executive ViewAI

Why It Matters

Organizations using Kiteworks Secure Data Forms should be aware of moderate risk from CVE-2026-23636, a unrestricted file upload vulnerability rated CVSS 5.5. This could allow unauthorized file access. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: restrict file access via WAF, implement allowlists.

Threat Intelligence Overview

EPSS Score
0.0%
Top 89% exploitable
Data Quality
5 sources
Confidence: Medium
EUVD NVD CVE.org EPSS Vulnrichment GitHub VulDB

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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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
Defer
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
Low
Technical Impact
Partial

Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
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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