CVE-2023-49558 in YASM
Summary
by MITRE • 01/03/2024
An issue in YASM 1.3.0.86.g9def allows a remote attacker to cause a denial of service via the expand_mmac_params function in the modules/preprocs/nasm/nasm-pp.c component.
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Analysis
by VulDB Data Team • 06/03/2025
The vulnerability identified as CVE-2023-49558 resides within the YASM assembler version 1.3.0.86.g9def, specifically within the modules/preprocs/nasm/nasm-pp.c file. This issue manifests as a remote denial of service condition that can be exploited by attackers who do not require authentication to compromise the affected system. The vulnerability is particularly concerning because it affects the expand_mmac_params function, which serves as a critical component in the preprocessing stage of the assembly process. The YASM assembler is widely used in software development environments for converting assembly language source code into object files, making this vulnerability impactful across numerous development and deployment scenarios.
The technical flaw within the expand_mmac_params function represents a classic case of improper input validation and memory handling that leads to resource exhaustion or application instability. When processing certain malformed input parameters, the function fails to properly handle edge cases or boundary conditions, resulting in unpredictable behavior that can manifest as a denial of service. This type of vulnerability typically stems from inadequate bounds checking or failure to validate parameter values before processing, allowing malicious input to trigger unexpected execution paths. The vulnerability operates at the preprocessing level of the assembler, meaning that attackers can craft specific input sequences that cause the tool to consume excessive resources or enter an infinite loop, thereby preventing legitimate assembly operations from completing successfully.
The operational impact of CVE-2023-49558 extends beyond simple service interruption, as it affects the entire software development lifecycle where YASM is utilized. Development teams relying on this assembler for building applications may experience complete build failures when encountering malicious input, potentially halting entire development pipelines and deployment processes. The remote nature of the attack means that attackers can exploit this vulnerability from external networks without requiring physical access or prior system compromise, making it particularly dangerous in environments where the assembler is exposed to untrusted input sources such as third-party libraries or user-generated content. Organizations using YASM in automated build systems, continuous integration pipelines, or security-sensitive applications face significant operational risks as this vulnerability can be leveraged to disrupt critical software delivery processes.
Mitigation strategies for CVE-2023-49558 should focus on immediate patching of the affected YASM version, as this represents the most effective solution to address the root cause of the vulnerability. Organizations should prioritize updating to the latest stable release of YASM that contains fixes for this specific issue, as the vulnerability affects core preprocessing functionality that is integral to the tool's operation. Additionally, implementing input validation controls at the system level can provide temporary protection by filtering out malformed parameters before they reach the vulnerable function. Security teams should also consider monitoring for unusual resource consumption patterns or failed assembly operations that might indicate exploitation attempts. From a broader security perspective, this vulnerability aligns with CWE-129, which addresses improper validation of array indices, and may be categorized under ATT&CK technique T1499.004 for network denial of service. Organizations should also implement network segmentation and access controls to limit exposure of systems running YASM to untrusted input sources, while maintaining regular security assessments to identify similar vulnerabilities in other development tools and components within their software supply chain.