CVE-2026-83603 in Netdata
Summary
by MITRE • 09/22/2026
Netdata is an open source observability tool. Prior to 2.10.4, the setuid-root ndsudo helper command fail2ban-client-status-socket in src/collectors/utils/ndsudo.c accepts a caller-controlled --socket_path from the low-privileged netdata service account. The account can direct root fail2ban-client to a malicious UNIX socket, and fail2ban/client/csocket.py CSocket.receive() passes the returned data to pickle.loads(), allowing attacker-controlled code to execute as root on systems with fail2ban-client installed. This issue is fixed in version 2.10.4 and nightly build 2.10.0-782-nightly.
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Analysis
by VulDB Data Team • 09/22/2026
The vulnerability identified involves a critical privilege escalation flaw within the Netdata observability platform, specifically affecting versions prior to 2.10.4. This issue stems from an insecure configuration of the ndsudo helper utility located in src/collectors/utils/ndsudo.c. The ndsudo tool is designed as a setuid-root binary, meaning it executes with root privileges regardless of which user invokes it. In vulnerable configurations, this privileged component interacts with fail2ban-client-status-socket and accepts a caller-controlled parameter named --socket_path from the low-privileged netdata service account. This design flaw allows an attacker who has compromised or gained access to the netdata service context to manipulate the socket path used for communication with the fail2ban client.
The operational impact of this vulnerability is severe, as it enables arbitrary code execution in a privileged root context on systems where fail2ban-client is installed and configured. The attack vector relies on the interaction between Netdata's ndsudo helper and the Python-based fail2ban client. When the netdata service account directs fail2ban-client to connect via a UNIX socket specified by the attacker, it establishes communication with a malicious endpoint controlled by the adversary. Upon receiving data from this malicious socket, the fail2ban/client/csocket.py module invokes CSocket.receive(), which subsequently passes the received payload directly to pickle.loads().
The core technical flaw lies in Python's pickle deserialization mechanism, which is inherently unsafe when processing untrusted input. The pickle module can deserialize arbitrary Python objects, including those that execute code during instantiation or loading. By supplying a crafted malicious object through the controlled socket path, an attacker triggers this insecure deserialization process within the context of the root-privileged fail2ban-client process. This results in the immediate execution of attacker-controlled commands with full system privileges, effectively bypassing all standard user-level security controls and granting complete control over the host operating system.
This vulnerability aligns with CWE-502, which describes Deserialization of Untrusted Data, a common source of remote code execution vulnerabilities in applications that utilize serialization frameworks without proper validation or sandboxing. Furthermore, from an offensive cybersecurity perspective, this exploit path corresponds to ATT&CK technique T1610, specifically the Drop and Execute sub-technique, where attackers deploy malicious payloads via legitimate system utilities to achieve persistence and privilege escalation. The use of a setuid binary as a bridge for untrusted input amplifies the risk significantly compared to standard application-level vulnerabilities.
To mitigate this vulnerability, organizations must immediately upgrade Netdata to version 2.10.4 or later, where the ndsudo helper has been patched to restrict or validate socket path inputs appropriately. For environments unable to update immediately, it is advisable to disable any integrations with fail2ban-client if not strictly required, thereby removing the attack surface entirely. Additionally, implementing strict file system permissions and monitoring for unusual process executions involving setuid binaries can help detect potential exploitation attempts. Security teams should also review their pickle usage patterns across all services to ensure that no other components are susceptible to similar insecure deserialization attacks by enforcing allowlists of serializable classes or switching to safer serialization formats like JSON where applicable.