CVE-2026-81575 in CodeMeter Runtime
Summary
by MITRE • 08/27/2026
If configured as a server, CodeMeter Runtime before versions 8.41a and 9.10 accepts requests with opcode 0x5e, which contain the data length and the data itself. Missing bounds checking on the data length value can lead to out of bounds reads, causing a segmentation fault that ultimately crashes the CodeMeter Runtime.
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified in CodeMeter Runtime versions prior to 8.41a and 9.10 represents a critical security flaw rooted in improper input validation within the software's server-side processing logic. When operating in server mode, the application is designed to accept incoming network requests that contain specific opcodes indicating the type of operation requested by the client. Among these operations is opcode 0x5e, which instructs the runtime to process a payload consisting of a data length field followed immediately by the corresponding data buffer. The core technical deficiency lies in the absence of rigorous bounds checking on the integer value representing this data length before it is utilized for memory allocation or read operations. This oversight allows an attacker to supply a maliciously crafted request where the declared data length exceeds the actual available memory space or valid boundaries within the application's allocated buffers.
From a technical perspective, this flaw constitutes an out-of-bounds read vulnerability, which aligns with Common Weakness Enumeration identifier CWE-125: Out-of-Bounds Read. When the runtime processes the opcode 0x5e request, it attempts to access memory locations based on the unvalidated length parameter provided by the client. If this value is artificially inflated or set to an invalid range that surpasses the allocated heap or stack limits, the application will attempt to read from unauthorized memory addresses. In environments governed by strict memory protection mechanisms such as those found in modern operating systems, accessing unmapped or protected memory triggers a segmentation fault. This hardware-level exception forces the CodeMeter Runtime process to terminate abruptly and unexpectedly, resulting in a denial of service condition for any legitimate users relying on the software's licensing management capabilities.
The operational impact of this vulnerability is primarily focused on availability rather than confidentiality or integrity at this stage. Because the flaw leads directly to a crash via segmentation fault, an unauthenticated attacker can exploit it remotely by sending specially crafted packets over the network interface exposed by the CodeMeter server service. This capability enables a straightforward denial-of-service attack where continuous exploitation would render the licensing infrastructure unavailable, disrupting applications that depend on valid license verification from this specific runtime environment. While out-of-bounds reads are sometimes precursors to arbitrary code execution if combined with other vulnerabilities such as use-after-free conditions or heap corruption techniques, in this specific context, the immediate and confirmed consequence is process termination due to memory protection violations.
To mitigate this risk, organizations running CodeMeter Runtime servers must prioritize upgrading to version 8.41a or later for the legacy branch, or version 9.10 and above for the newer architecture, as these releases contain the necessary patches implementing proper input validation logic. Until an upgrade is feasible, administrators should consider network-level mitigations such as restricting access to the CodeMeter server ports using firewall rules to allow only trusted IP addresses, thereby reducing the attack surface available to potential adversaries. Additionally, deploying intrusion detection systems capable of identifying anomalous packet structures or excessive request rates can provide a layer of defense against automated exploitation attempts targeting this specific opcode handling flaw. This incident underscores the importance of rigorous input validation and bounds checking in network-facing services to prevent simple logic errors from escalating into significant availability disruptions.