CVE-2026-102510 in PLC4X
Summary
by MITRE • 09/30/2026
Integer Overflow, Improper Validation of Array Index, Uncontrolled Recursion and Memory Allocation with Excessive Size Value in the Go implementation of Apache PLC4X (PLC4Go) allow a malicious device, or an attacker able to inject network traffic, to crash or exhaust the memory of the client application, causing a denial of service.
The individual defects are: - Generated parsers pre-allocate arrays with the element count claimed on the wire (0.13.0 through 0.13.1). - Transport read helpers allocate buffers of the size claimed on the wire without an upper bound. - ADS and KNXnet/IP response handling indexes into received data without checking its length, causing a panic. - ADS and EIP frame-length handling accepts, or arithmetically wraps to, a length of zero, breaking message framing. - Recursive protocol types are parsed without a nesting-depth limit. The same defect in the Java implementation is covered by CVE-2026-102509 https://cveprocess.apache.org/cve5/CVE-2026-102509 .
Additionally, length and position arithmetic in generated serializers was performed in 16-bit integers. If an application forwards attacker-influenced payloads larger than 8 KB, the length field wraps, and the remainder of the payload may be interpreted by the receiving device (for example, an ADS PLC) as additional, independent protocol messages.
This issue affects Apache PLC4X: from 0.11.0 before 1.0.0. PLC4Go is consumed as the Go module github.com/apache/plc4x/plc4go; versions refer to the corresponding Apache PLC4X releases.
Users are recommended to upgrade to version 1.0.0, which fixes the issue.
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Analysis
by VulDB Data Team • 09/30/2026
The vulnerability landscape surrounding the Go implementation of Apache PLC4X, known as PLC4Go, presents a critical set of flaws that compromise the integrity and availability of industrial control systems relying on this library for protocol communication. These defects span multiple categories including integer overflow, improper validation of array indices, uncontrolled recursion, and memory allocation with excessive size values. The core issue stems from insufficient input validation and bounds checking when processing network traffic generated by or injected into PLC4Go clients. A malicious device or an attacker capable of injecting crafted network packets can exploit these weaknesses to cause a denial of service condition by crashing the application or exhausting its available memory resources, thereby disrupting industrial operations that depend on stable communication with programmable logic controllers and other field devices.
A primary technical flaw involves the generation of parsers in versions 0.13.0 through 0.13.1 which pre-allocate arrays based directly on element counts claimed within the incoming data stream without verifying if those counts are reasonable or bounded by system limits. This behavior aligns with CWE-789, an integer overflow that leads to a buffer over-read or write, and CWE-400, uncontrolled resource consumption. By trusting external input for memory allocation sizes, the application becomes susceptible to rapid memory exhaustion when faced with large claimed array sizes. Similarly, transport read helpers allocate buffers of the size specified in the wire data without enforcing an upper bound limit. This lack of constraint allows attackers to trigger massive memory allocations that can quickly deplete system resources, leading to service degradation or complete failure.
Further compounding these issues are defects in the handling of specific industrial protocols such as ADS and KNXnet/IP where response handling indexes into received data structures without first validating their length against expected bounds. This improper validation leads directly to panic conditions when out-of-bounds access occurs, representing a classic CWE-125 or CWE-787 vulnerability depending on whether it results in information disclosure or memory corruption. Additionally, the frame-length handling logic for ADS and EIP protocols fails to reject zero-length frames correctly; instead, it accepts them or allows arithmetic wrapping that results in a length of zero. This breaks message framing integrity, allowing malformed packets to disrupt protocol state machines and potentially cause undefined behavior within the application stack.
The vulnerability extends into recursive parsing mechanisms where protocol types are processed without any imposed nesting-depth limit. Uncontrolled recursion is a significant risk factor categorized under CWE-675, as it can lead to stack overflow errors or excessive CPU consumption depending on implementation details. This defect mirrors issues found in other implementations of the same ecosystem and highlights a systemic failure to enforce depth limits during recursive data structure traversal. The presence of such flaws means that deeply nested malicious payloads can crash the parser engine entirely, preventing further legitimate communication attempts until service restart is performed manually or via automated recovery mechanisms which may not be present in all industrial environments.
In addition to parsing vulnerabilities, serialization logic contains critical arithmetic defects where length and position calculations are performed using 16-bit integers rather than larger data types capable of handling substantial payload sizes. When an application forwards attacker-influenced payloads exceeding eight kilobytes, the length field wraps around due to integer overflow constraints inherent in 16-bit signed or unsigned arithmetic operations. This wrapping effect causes the remainder of the oversized payload to be misinterpreted by receiving devices, such as ADS PLCs, as separate independent protocol messages rather than a single fragmented unit. This scenario creates severe security implications including message injection and potential command execution if subsequent fragments contain malicious instructions, aligning with CWE-190 integer overflow errors that lead to unexpected behavior in network protocols.
The impact of these vulnerabilities is profound for organizations utilizing Apache PLC4X versions from 0.11.0 up to but not including version 1.0.0. Since PLC4Go operates as a Go module consumed via github.com/apache/plc4x/pllcgo, any application depending on these earlier releases inherits the associated risks. The ability for remote attackers to crash services or manipulate message boundaries poses significant threats to operational technology environments where reliability and security are paramount. Attackers leveraging ATT&CK techniques such as T1498 Network Denial of Service can exploit these flaws to disrupt production lines, while those aiming for data integrity violations might use the serialization wrapping flaw to inject unauthorized commands into PLCs by fragmenting malicious payloads across multiple perceived messages.
To mitigate these risks, immediate action is required to upgrade all affected systems to Apache PLC4X version 1.0.0 or later releases where these defects have been addressed. The updated versions implement proper bounds checking for array allocations, enforce upper limits on buffer sizes during transport reads, validate index ranges before accessing received data structures, and introduce depth limits for recursive parsing operations. Furthermore, the serialization logic has likely been corrected to use appropriate integer widths that prevent wrapping issues with large payloads. Organizations should also consider implementing network-level filtering rules to restrict traffic from untrusted sources if upgrading is not immediately feasible, although this serves only as a compensating control rather than a complete solution given the depth of the application-layer flaws. Regular security audits and dependency updates remain essential practices for maintaining robust industrial cybersecurity postures against evolving threats targeting PLC communication stacks.