CVE-2026-83601 in Netdata
Summary
by MITRE • 09/22/2026
Netdata is an open source observability tool. Prior to 2.10.4, an authenticated child agent can send an oversized DIMENSION SLOT value that str2ull_encoded passes to pluginsd_rrddim_put_to_slot in src/plugins.d/pluginsd_internals.h without an upper bound. prd_array_create in src/database/rrdset-pluginsd-array.h can then wrap the size_t allocation calculation while retaining the original large array size, causing the subsequent initialization loop to write beyond the undersized heap allocation and crash the parent agent. 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
Netdata serves as a widely deployed open-source observability platform designed to monitor system metrics, application performance, and infrastructure health across diverse environments. The software architecture relies on a parent-child agent model where child agents collect data from local sources and transmit it to the central parent agent for aggregation and visualization. This distributed design introduces specific attack surfaces related to inter-agent communication protocols. A critical vulnerability exists in versions of Netdata prior to 2.10.4, specifically within the mechanism that processes dimension slot values sent by authenticated child agents. The flaw resides in the handling of numeric string conversions during data ingestion, where input validation is insufficiently rigorous against integer overflow conditions.
The technical root cause involves a failure to enforce upper bounds on the DIMENSION SLOT value transmitted from an authenticated child agent. When this oversized value is processed, it passes through the str2ull_encoded function and subsequently reaches pluginsd_rrddim_put_to_slot in src/plugins.d/pluginsd_internals.h without adequate range checking. The critical security flaw occurs during memory allocation within prd_array_create located in src/database/rrdset-pluginsd-array.h. Here, a size_t calculation for array sizing undergoes integer wraparound due to the excessively large input value. Although the calculated allocation size becomes small or zero due to this overflow, the original large logical array size is retained internally by the application logic. This discrepancy creates a severe mismatch between the allocated heap memory and the expected data structure dimensions.
The operational impact of this vulnerability manifests as a denial-of-service condition affecting the parent Netdata agent. Following the undersized heap allocation, the system proceeds to execute an initialization loop that attempts to write data based on the original large size into the insufficiently sized buffer. This results in a heap-based out-of-bounds write operation. Such memory corruption typically leads to immediate application instability and crashes of the parent process. For administrators relying on Netdata for continuous monitoring, this crash disrupts visibility into infrastructure health metrics, potentially obscuring critical security events or performance degradations occurring elsewhere in the monitored environment. The exploitation requires authentication, meaning an attacker must possess valid credentials for a child agent node to trigger this condition.
Mitigation strategies primarily involve upgrading the Netdata installation to version 2.10.4 or later, where the developers have implemented proper bounds checking and integer overflow protection within the relevant data processing functions. For environments unable to upgrade immediately, network segmentation policies should be enforced to restrict communication between child agents and parent agents to trusted networks only. Additionally, enforcing strong authentication mechanisms such as mutual TLS can reduce the risk of unauthorized entities attempting to exploit this flaw even if they gain access to a node that could act as an agent. From a classification perspective, this vulnerability aligns with CWE-190 Integer Overflow or Wraparound and CWE-787 Out-of-bounds Write within the Common Weakness Enumeration framework. In terms of adversary behavior, it relates to ATT&CK technique T1499 Endpoint Denial of Service, as the exploitation results in service disruption rather than data exfiltration or privilege escalation.