CVE-2026-81574 in CodeMeter Runtime
Summary
by MITRE • 08/27/2026
In CodeMeter Runtime before versions 8.41a and 9.10, the logger does not sanitize input strings in certain cases, allowing an attacker to inject printf-style format specifiers. This can be used to reliably crash CodeMeter and disclose sensitive information such as process memory and stack canaries. The attack works locally, for example by using cmu --set-proxy to set the proxy value, and remotely when combined with CVE-2026-81573 by setting General.ProxyServer and then triggering this vulnerability.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/27/2026
The identified vulnerability in CodeMeter Runtime versions prior to 8.41a and 9.10 constitutes a critical security flaw rooted in improper input sanitization within the application's logging subsystem. Specifically, the logger fails to validate or escape user-supplied strings before passing them to printf-style formatting functions. This architectural oversight allows an attacker to inject format specifiers such as %x, %s, or %n into log entries. When these unsanitized inputs are processed by the vulnerable function, they are interpreted not as literal text but as instructions for memory access and manipulation. This behavior aligns with CWE-134, which classifies vulnerabilities involving the use of externally-controlled format strings that can lead to arbitrary code execution or information disclosure. The presence of this flaw indicates a fundamental failure in input validation practices during the construction of log messages, where developer assumptions about data safety were not enforced through rigorous sanitization protocols.
The operational impact of this vulnerability is severe, primarily manifesting as both denial of service and sensitive information leakage. By injecting specific format specifiers, an attacker can cause the CodeMeter application to crash reliably, resulting in a local or remote denial of service depending on the attack vector utilized. More critically, the ability to read from arbitrary memory locations enables the disclosure of process memory contents. This includes stack canaries, which are security mechanisms designed to detect buffer overflows and prevent exploitation. The exposure of these cryptographic values undermines the integrity of other potential defenses within the application environment. Furthermore, accessing heap or stack data may reveal sensitive operational information such as encryption keys, session tokens, or internal state variables that were not intended for public consumption. This level of memory disclosure significantly expands the attack surface by providing attackers with the contextual knowledge required to craft more sophisticated exploits against the host system.
The exploitability of this vulnerability varies based on the access context and integration with other flaws. Locally, an attacker can trigger the condition directly through legitimate administrative interfaces or command-line tools provided by CodeMeter, such as using the cmu utility to set proxy values that are subsequently logged without sanitization. This local vector requires initial access to the system but offers a straightforward path to exploitation due to the direct interaction with vulnerable logging functions. However, the threat landscape is amplified when this vulnerability is combined with CVE-2026-81573. In scenarios where an attacker can remotely set configuration parameters like General.ProxyServer through network-facing interfaces, they can inject malicious format strings that are then processed by the logger upon subsequent operations. This combination transforms a local information disclosure flaw into a remote code execution or denial-of-service vector, significantly increasing its severity and potential for widespread impact across distributed environments relying on CodeMeter for license management and digital rights protection.
Mitigation strategies must prioritize immediate patching to address the root cause of the input validation failure. Organizations running affected versions should upgrade to CodeMeter Runtime version 8.41a or later, where this logging sanitization issue has been resolved by implementing strict output encoding and parameterized logging approaches that prevent format specifier interpretation. In environments where upgrading is not immediately feasible, defensive measures such as restricting access to administrative interfaces like cmu can reduce the local attack surface. Additionally, deploying intrusion detection systems capable of identifying anomalous log patterns or memory access violations may help in detecting attempted exploitation activities. From a broader security architecture perspective, this incident underscores the importance of adhering to secure coding standards that mandate input validation at all entry points and the use of safe logging APIs that do not interpret user data as format strings. Aligning with MITRE ATT&CK techniques related to Discovery and Defense Evasion can help in monitoring for indicators of such memory disclosure attempts, ensuring that any exploitation activity is detected before it leads to full system compromise or persistent denial of service conditions.