CVE-2026-24756: Kiteworks IDOR Vulnerability – Unauthorized Data Modification Risk

Technical summary

CVE-2026-24756 is an Insecure Direct Object Reference (IDOR) vulnerability in Kiteworks Secure Data Forms. The vulnerability arises from insufficient authorization checks when users attempt to modify resources. The application accepts requests from authenticated users but does not adequately validate that the requester owns or has permission to modify the targeted resource. This is a common authorization flaw where direct object references (such as resource IDs) are exposed in requests without proper ownership validation. An attacker can craft requests to modify resources belonging to other users by manipulating these references. The CVSS 3.1 score of 4.3 reflects a network-accessible vulnerability requiring prior authentication, with low attack complexity and integrity impact but no confidentiality or availability impact.

Business impact

This vulnerability could allow competitors, malicious insiders, or compromised user accounts to alter sensitive data forms and templates within Kiteworks deployments. Organizations using Kiteworks for regulated data handling—such as healthcare, financial services, or legal firms—face potential compliance violations if unauthorized modifications occur. The reputational risk includes loss of trust in data integrity guarantees. While the direct technical impact is limited to modification of form resources, the business consequence depends on what data flows through those forms and how extensively they're used in business processes.

Affected systems

Kiteworks (Accellion Kiteworks) prior to version 9.3.0 is affected. This includes all deployments running versions before 9.3.0, whether on-premises or in managed hosting configurations. Organizations should audit their Kiteworks deployment version immediately to determine exposure.

Exploitability

Exploitation requires valid user credentials, making this a low-volume attack vector compared to unauthenticated vulnerabilities. However, it's highly likely to occur in environments with multiple users or where accounts have been compromised. The attack requires no user interaction, no special network positioning, and no exploit complexity—an attacker simply needs to identify the resource IDs of other users' forms and submit modification requests. The straightforward nature of IDOR attacks means exploitation is trivial once an attacker understands the API or interface structure.

Remediation

Upgrade all Kiteworks instances to version 9.3.0 or later. This version includes authorization checks that verify resource ownership before allowing modifications. Organizations should test the upgrade in a non-production environment first to ensure compatibility with existing integrations and workflows.

Patch guidance

Verify that your Kiteworks deployment version by checking the administration console or support portal. If running any version prior to 9.3.0, initiate an upgrade using the vendor's standard upgrade procedures. Accellion provides upgrade documentation in their support portal—follow those procedures to minimize downtime. For managed or hosted deployments, contact your Kiteworks service provider to confirm patch status and scheduling.

Detection guidance

Monitor Kiteworks audit logs for modification requests on resources by users who do not own or typically access those resources. Look for patterns where a single user is modifying resources across multiple other users' accounts or unusual access to shared form templates. API calls that reference resource IDs not associated with the requesting user may indicate exploitation attempts. Enable enhanced logging if available and correlate Kiteworks activity logs with user account activity to identify suspicious patterns.

Why prioritize this

Although the CVSS score is moderate (4.3), prioritize this patch because IDOR vulnerabilities are well-understood, trivial to exploit once discovered, and often discovered by opportunistic attackers. The vulnerability affects data integrity in a product designed for secure data handling, amplifying business risk. The fix is straightforward and requires only a version upgrade, making remediation low-friction compared to many vulnerabilities.

Risk score, explained

The CVSS 3.1 score of 4.3 (MEDIUM severity) reflects the requirement for authentication (lowering impact vs. unauthenticated flaws) and the limited scope of impact (integrity only, not confidentiality or availability). The score appropriately penalizes the vulnerability for being network-accessible and requiring no user interaction, but does not fully capture the business risk in regulated environments or the likelihood of exploitation by insiders with valid accounts.

Frequently asked questions