CVE-2026-90448 in Malcolm
Summary
by MITRE • 09/12/2026
A deployment mode intended to expose only read access to stored data proxies a set of application programming interface routes without restricting which request methods are allowed. One such route accepts a request that creates or overwrites a stored record, including an attacker-chosen identifier, using the application's own elevated backend credentials. This allows an authenticated user on a deployment intended to be read-only to forge or overwrite stored records that should not be modifiable in that deployment mode.
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Analysis
by VulDB Data Team • 09/12/2026
The vulnerability described constitutes a critical authorization bypass within a specific deployment configuration designed for data integrity and security through restricted access. In this scenario, the system is configured with a deployment mode intended to expose only read-only access to stored data proxies. This architectural decision implies that clients interacting with these endpoints should be limited to retrieving information without the ability to alter, create, or delete existing records. However, the underlying implementation fails to enforce this restriction at the application programming interface level by proxying a set of routes without adequately filtering or restricting the HTTP request methods allowed for those specific endpoints. This oversight creates a significant gap between the intended security posture and the actual operational behavior of the system.
At the technical core, one particular route within this proxied set accepts requests that result in the creation or overwriting of stored records. Crucially, this operation allows an attacker to specify their own identifier for the new or modified record. The severity of this flaw is amplified by the fact that these operations are executed using the application's own elevated backend credentials rather than the permissions associated with the authenticated user making the request. This means that even though a user may only have read-only privileges in the intended deployment mode, they can leverage this misconfigured route to perform write operations as if they were an administrator or service account with full database modification rights. The ability to forge records by choosing arbitrary identifiers further exacerbates the risk, potentially allowing for identity spoofing, data injection attacks, or the corruption of critical system states that rely on unique and trusted record keys.
From a security classification perspective, this vulnerability aligns closely with CWE-269 Improper Privilege Management, as it involves an actor obtaining privileges they are not authorized to have by exploiting a flaw in access control logic. Additionally, because the attack requires authentication but bypasses intended restrictions on actions available to that authenticated user, it also relates to CWE-862 Missing Authorization. In terms of adversary tactics, this behavior is consistent with techniques found in the MITRE ATT&CK framework under Privilege Escalation or Defense Evasion, specifically where an attacker manipulates API endpoints to perform unauthorized data modifications. The use of elevated backend credentials for these actions indicates a failure in proper credential scoping and separation of duties within the application's architecture.
The operational impact of this vulnerability is severe, as it completely undermines the security guarantees provided by the read-only deployment mode. An authenticated attacker can forge new records or overwrite existing ones with malicious content, leading to data integrity loss, potential system compromise if those records influence downstream processes, and a breach of trust in the application's ability to protect stored information. This could lead to financial loss, reputational damage, or further exploitation vectors depending on the nature of the forged data. For instance, forging an administrative record could allow for subsequent lateral movement within the organization’s infrastructure.
To mitigate this vulnerability, immediate remediation efforts should focus on enforcing strict method restrictions at the proxy and application layers. The deployment mode intended to be read-only must explicitly reject all non-GET or non-HEAD HTTP methods such as POST, PUT, PATCH, and DELETE for the relevant API routes. Furthermore, access control checks must be implemented to ensure that write operations are only permitted when authenticated users possess explicit write permissions, regardless of the proxy configuration. It is also essential to review how backend credentials are utilized; they should not be used indiscriminately for all proxied requests but rather scoped appropriately based on the user's actual role and the intended operation type. Regular security audits and penetration testing focused on API endpoint configurations will help identify similar misconfigurations in other parts of the application infrastructure.