CVE-2026-115793 in P-Net
Summary
by MITRE • 10/29/2026
P-Net before 1.0.3 does not release the RPC session allocated for an RPC request that names an unknown interface or object UUID, and does not start a timeout for it. Repeated requests with different activity UUIDs exhaust the available sessions. Once they are exhausted the device no longer answers new RPC requests, including Endpoint Mapper Lookup and Connect, until it is restarted. A remote unauthenticated attacker can use this to cause a denial of service.
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Analysis
by VulDB Data Team • 10/29/2026
The vulnerability identified in P-Net versions prior to 1.0.3 represents a critical resource management failure within the Remote Procedure Call (RPC) subsystem. This flaw specifically affects how the application handles RPC requests that target unknown or invalid interface and object Universally Unique Identifiers (UUIDs). Under normal operational conditions, an RPC server should validate incoming request headers against known interfaces before allocating significant system resources such as session contexts. However, in this vulnerable implementation, the software proceeds to allocate a full RPC session for any request, regardless of whether the specified UUID corresponds to a registered or valid interface on the target device. This behavior indicates a fundamental lack of pre-validation checks at the entry point of the RPC handling logic, allowing external actors to trigger resource-intensive operations without proper authorization or context verification.
The core technical flaw lies in the absence of session lifecycle management for these invalid requests. When an attacker sends a request with an unknown UUID, P-Net allocates memory and state structures associated with that session but fails to initiate any timeout mechanism to reclaim those resources if no further communication occurs. In standard RPC implementations, sessions are typically bound by strict timeouts or require explicit termination signals. Here, the allocated sessions persist indefinitely in memory until explicitly closed by a valid interaction, which never happens for these malformed requests. This design oversight means that each malicious request consumes a finite pool of available session slots without ever releasing them back to the system's resource manager.
The operational impact of this vulnerability is severe and directly leads to a denial of service condition. Because the number of concurrent RPC sessions supported by P-Net is limited, an unauthenticated remote attacker can systematically exhaust these resources by sending a high volume of requests with varying activity UUIDs. As each request consumes one session slot without releasing it, the device's capacity to handle new connections diminishes rapidly. Once the pool of available sessions is fully depleted, the application becomes unable to process any further incoming RPC traffic. This includes critical system-level functions such as Endpoint Mapper Lookups and Connect requests, which are essential for establishing legitimate communication channels with other services on the network. Consequently, the device effectively freezes in terms of its remote management capabilities until a manual restart clears the exhausted session table.
From a security classification perspective, this vulnerability aligns closely with CWE-400, Uncontrolled Resource Consumption, as it involves the exhaustion of system resources due to improper handling of external input. Furthermore, the exploitation technique maps directly to MITRE ATT&CK tactic T1499, Endpoint Denial of Service, specifically under sub-techniques involving resource exhaustion through application layer attacks. The attack vector is remote and unauthenticated, meaning no prior access credentials are required to trigger this denial of service state, significantly lowering the barrier for exploitation by malicious actors on the same network segment or those with routed access to the management interface.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary solution is to upgrade P-Net to version 1.0.3 or later, where this resource leak has been addressed through improved session validation and timeout enforcement mechanisms. For environments where an immediate patch is not feasible, network-level controls should be implemented to restrict access to the RPC ports used by P-Net, ensuring that only trusted management stations can initiate connections. Additionally, implementing rate limiting on incoming RPC requests can help mitigate the speed at which sessions are exhausted, providing a temporary buffer against automated exploitation attempts while permanent fixes are deployed. Regular monitoring of session counts and resource utilization metrics is also recommended to detect potential abuse early before total service degradation occurs.