CVE-2026-90454 in Malcolm
Summary
by MITRE • 09/12/2026
A deployment mode intended to expose only read access to a bundled packet-analysis component's interface denies a list of write-capable routes by pattern, but the pattern omits routes that modify tags attached to stored session records, and the proxy configuration otherwise permits the request method those routes use. This allows an authenticated user on a deployment intended to be read-only to add or remove tags on stored session records.
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Analysis
by VulDB Data Team • 09/12/2026
The vulnerability described constitutes a critical authorization bypass within a network packet analysis system, specifically affecting deployments configured for read-only access. In such environments, the primary security objective is to restrict users from modifying data, ensuring that analysts can review historical traffic and sessions without altering the integrity of stored records or introducing new artifacts into the dataset. The underlying architectural flaw lies in the implementation of an access control mechanism designed to filter HTTP routes based on pattern matching rules intended to block write operations. While this filtering logic successfully denies requests targeting standard modification endpoints, it fails to account for a specific subset of API paths associated with metadata management, particularly those responsible for modifying tags attached to stored session records. This oversight creates a significant gap in the security boundary, allowing authenticated users to perform state-changing actions despite being granted only read privileges.
From a technical perspective, this issue is classified as an Insecure Direct Object Reference or more accurately, a Broken Access Control vulnerability where the enforcement logic relies on superficial pattern matching rather than comprehensive method-level checks for all mutable resources. The attacker exploits the fact that the proxy configuration permits the specific HTTP methods used by these tag-modification routes while relying on a regex or string-based filter to deny other write operations. Because the pattern explicitly omits the paths related to session tagging, the system processes these requests as valid read-only interactions when they are actually performing update operations. This allows an authenticated user to add new tags to existing sessions or remove existing ones, effectively altering the state of the database without triggering the intended security controls. The impact extends beyond simple data modification; it compromises the auditability and integrity of network forensics by allowing users to manipulate how traffic is categorized and labeled, which can be used to hide malicious activity from other analysts or create false positives in automated detection systems.
In terms of industry standards, this vulnerability aligns with CWE-269 Improper Privilege Management and CWE-862 Missing Authorization, as the system fails to enforce proper restrictions on what an authenticated user is allowed to do. Furthermore, it maps directly to MITRE ATT&CK technique T1078 Valid Accounts, where adversaries leverage legitimate credentials to access resources they should not have permission to modify. The ability to alter metadata such as tags can also facilitate lateral movement or persistence in a broader attack chain by manipulating how security tools prioritize and display alerts. For instance, an attacker could tag malicious traffic with benign labels to evade detection rules that rely on specific tag values for triggering high-severity alerts.
To mitigate this vulnerability, the immediate remediation involves updating the route filtering logic to explicitly include all endpoints capable of modifying session metadata in the deny list, regardless of their specific path structure. A more robust long-term solution is to implement role-based access control (RBAC) that evaluates permissions at the resource and action level rather than relying solely on URL pattern matching. This ensures that any API endpoint performing write operations requires explicit authorization checks independent of its location within the application hierarchy. Additionally, implementing strict HTTP method validation for all endpoints associated with mutable data can prevent unintended state changes even if path-based filters are bypassed. Regular security audits and penetration testing focused on access control logic should be conducted to identify similar gaps in other parts of the packet analysis interface before they can be exploited by malicious actors seeking to compromise the integrity of network monitoring systems.