CVE-2026-102726 in NetX Duo
Summary
by MITRE • 09/29/2026
Unbounded PPP IPCP Option Parsing Causes a Worker Stall and Out-of-bounds Read
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified in the Point-to-Point Protocol (PPP) Internet Control Protocol (IPCP) implementation represents a critical flaw within network stack processing logic, specifically affecting devices that handle dial-up or serial WAN connections. This issue stems from an unbounded parsing mechanism when handling IPCP configuration options during the negotiation phase of PPP link establishment. The protocol relies on variable-length fields to exchange parameters such as IP addresses and DNS servers between peers. In this specific instance, the software fails to validate the length field associated with these incoming options against the actual buffer size or expected maximum limits defined by RFC 1332. Consequently, when a maliciously crafted packet containing an option with an excessively large length value is received, the parser proceeds to read beyond the allocated memory boundaries of the current data structure. This behavior classifies as CWE-125 Out-of-bounds Read, allowing for potential information disclosure or system instability depending on what lies adjacent in memory.
The operational impact of this flaw extends beyond simple data leakage due to the specific nature of how modern operating systems handle network packet processing. The vulnerability triggers a worker stall, indicating that the thread responsible for processing PPP frames enters an infinite loop or hangs while attempting to process the malformed input. This denial-of-service condition effectively blocks further communication on the affected interface and can potentially impact other system resources if the stalled worker is part of a shared pool used by multiple network services. An attacker positioned at the remote end of the connection, such as through a compromised ISP infrastructure or via physical access in local loop scenarios, could exploit this to disrupt service availability for legitimate users. From an offensive security perspective, this aligns with MITRE ATT&CK technique T1498 Network Denial of Service, where resource exhaustion is achieved by exploiting protocol parsing inefficiencies rather than flooding the network with traffic volume.
Mitigation strategies must focus on strict input validation and defensive coding practices within the PPP stack implementation. Developers should enforce hard limits on all variable-length fields during the IPCP negotiation phase, ensuring that any option length does not exceed predefined maximums established in relevant RFC standards before attempting to parse or copy data into buffers. Implementing bounds checking prior to memory access is essential to prevent out-of-bounds reads and subsequent worker stalls. For system administrators unable to immediately patch affected firmware or software components, restricting PPP connections to trusted networks only can reduce the attack surface. Additionally, deploying intrusion detection systems capable of inspecting PPP frames for anomalous option lengths may provide a layer of defense against exploitation attempts in environments where legacy protocols remain active.