CVE-2026-43842 in ADAM-3600
Summary
by MITRE • 10/20/2026
A NULL pointer dereference vulnerability in the license manager service could allow an unauthenticated attacker to crash the service via the rpc_rx_fsm function when msglen is set to 0.
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Analysis
by VulDB Data Team • 10/20/2026
The identified vulnerability represents a critical stability issue within the license management subsystem, specifically manifesting as a null pointer dereception during remote procedure call processing. This flaw resides in the rpc_rx_fsm function, which serves as the finite state machine handler for incoming RPC messages. The core technical deficiency lies in the absence of robust input validation regarding message length parameters before memory access operations are executed. When an unauthenticated attacker constructs and transmits a maliciously crafted request where the msglen field is explicitly set to zero, the system fails to perform necessary boundary checks or null validations prior to attempting to dereference pointers associated with that message buffer. This lack of defensive programming allows execution flow to proceed into memory regions containing no valid data structures, triggering an immediate segmentation fault or access violation exception within the service process.
From a technical perspective, this vulnerability aligns closely with CWE-476, which defines NULL Pointer Dereference as a condition where software dereferences a pointer that it expects to be valid but is actually null. In the context of network-facing services like license managers, such errors are particularly dangerous because they can often be triggered remotely without requiring any form of authentication or prior session establishment. The rpc_rx_fsm function likely assumes that incoming messages will always contain at least minimal structural integrity, failing to account for malformed inputs from untrusted sources. By setting msglen to zero, the attacker effectively bypasses subsequent logic that would normally initialize or validate pointers based on message size, leading directly to a crash when the system attempts to read or write data associated with an empty payload.
The operational impact of this vulnerability is primarily centered around service availability and reliability rather than direct code execution or privilege escalation. Since the result of exploiting this flaw is typically a process termination or application restart, it constitutes a classic Denial of Service scenario. For license management services, which are often critical infrastructure components ensuring software compliance and access control across an organization, unexpected crashes can lead to significant operational disruptions. Users may be unable to activate products, validate licenses, or maintain ongoing sessions until the service is manually restarted by administrators. This creates a window of opportunity where security controls might be temporarily bypassed if the license check logic relies on continuous availability of this specific daemon. Furthermore, repeated exploitation could cause resource exhaustion through rapid restart cycles, potentially impacting system performance and stability beyond just the single affected process.
To mitigate this vulnerability, immediate remediation should focus on implementing strict input validation within the rpc_rx_fsm function. Developers must ensure that msglen is checked for validity before any pointer dereferencing or memory allocation occurs. Specifically, a check should be added to verify that msglen is greater than zero and does not exceed expected maximum buffer sizes. Additionally, defensive programming practices dictate that all pointers derived from external inputs should be validated against null values prior to use. On the infrastructure side, deploying network-level access controls can help restrict RPC traffic to trusted IP ranges or require authentication before any processing occurs, thereby preventing unauthenticated actors from reaching this vulnerable code path entirely. Regular security testing and fuzzing of RPC interfaces are also recommended to identify similar input validation gaps in other parts of the service architecture. This issue reflects a common pattern found in network services where assumptions about message integrity are not rigorously enforced, highlighting the importance of treating all external inputs as potentially hostile until proven otherwise according to principles outlined in ATT&CK techniques related to resource hijacking and denial of service via application layer attacks.