CVE-2026-86098 in nDPI
Summary
by MITRE • 09/05/2026
ntop nDPI versions before 6.0 contain a heap buffer overflow vulnerability in the ndpi_json_string_escape function that writes beyond caller-supplied buffer boundaries. Attackers can trigger the overflow by supplying crafted network packet data including TLS SNI, HTTP headers, or DNS names that reach the vulnerable function, causing heap corruption.
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Analysis
by VulDB Data Team • 09/05/2026
The nDPI library, a core component of the ntopng traffic analysis suite, contains a critical memory safety vulnerability in versions prior to 6.0 affecting the ndpi_json_string_escape function. This flaw manifests as a heap buffer overflow where the implementation fails to correctly validate input lengths before performing string escaping operations. The specific technical failure occurs when processing network protocol data that requires JSON serialization for logging or API output purposes. During this process, the function calculates an expected size for the escaped string but does not adequately account for all edge cases involving special characters or malformed inputs. Consequently, memory writes extend beyond the boundaries of the allocated heap buffer, leading to direct corruption of adjacent memory structures on the heap.
Attackers can exploit this vulnerability by crafting specific network packets designed to trigger the vulnerable code path within nDPI. The attack vector primarily involves injecting malicious payloads into protocol fields that are parsed and subsequently escaped for JSON output. Common targets include Transport Layer Security (TLS) Server Name Indication extensions, Hypertext Transfer Protocol HTTP headers, and Domain Name System DNS query names. When these crafted inputs reach the vulnerable function during deep packet inspection or traffic analysis operations, they cause the heap overflow condition. This memory corruption can lead to application crashes resulting in denial of service conditions for network monitoring systems. More critically, depending on the specific memory layout and exploitation techniques employed by an attacker, this flaw may allow for arbitrary code execution with the privileges of the ntopng process.
The operational impact of this vulnerability is significant for organizations relying on nDPI-based solutions for real-time traffic analysis and security monitoring. A successful exploit could compromise the integrity of the network visibility platform, allowing attackers to pivot into internal networks or exfiltrate sensitive data captured by the system. Furthermore, the instability caused by heap corruption can disrupt continuous monitoring capabilities, creating blind spots in an organization's defense-in-depth strategy. The vulnerability aligns with CWE-122 Heap-based Buffer Overflow and is relevant to ATT&CK technique T1059 Command and Scripting Interpreter if used for initial access or lateral movement via compromised network tools.
Mitigation strategies should prioritize immediate upgrading of the nDPI library to version 6.0 or later where this issue has been resolved through improved input validation and bounds checking in the string escaping logic. Until an upgrade is feasible, organizations can implement strict ingress filtering rules at perimeter firewalls to block malformed packets containing excessively long TLS SNI fields, HTTP headers, or DNS names that might trigger the overflow. Additionally, deploying intrusion detection systems with signatures targeting known exploitation patterns of heap overflows in network analysis tools can provide a layer of defense against active attacks. Regular patch management and vulnerability scanning are essential to maintain the security posture of infrastructure dependent on deep packet inspection technologies.