CVE-2022-49264 addresses a vulnerability in the Linux kernel related to the handling of the execve() system call when invoked with an empty argument vector (argv). The execve() function is used to execute a new program, and POSIX standards recommend that the first argument (argv[0]) be the filename of the program being executed. However, the Linux kernel historically allowed scenarios where argv could be NULL or empty (argc < 1), which is non-compliant with other operating systems and POSIX recommendations. This behavior was identified as problematic because it can lead to undefined or inconsistent behavior in user space and kernel space. The vulnerability was highlighted in the context of CVE-2021-4034 (PwnKit), where practical exploitation leveraged this argv handling flaw in shellcode. The fix implemented forces the kernel to inject a single empty string into argv when it is empty and adjusts argc accordingly to 1. This change ensures that execve() always receives a valid argv with at least one element, preventing the edge case of an empty argument list. Additionally, the kernel now warns when a process launches another with a NULL argv and rejects NULL argv usage for kernel threads. This patch also accounts for the additional stack space required due to the injected empty string. The change aims to improve security and stability by enforcing stricter argument handling in execve(), reducing the attack surface related to argument vector manipulation. The vulnerability does not have known exploits in the wild yet, and the fix was motivated by the potential for exploitation demonstrated in related vulnerabilities. The affected versions are various Linux kernel commits prior to the patch, and the issue is tracked in the Kernel Self Protection Project (KSPP).

For European organizations, the impact of CVE-2022-49264 primarily concerns systems running vulnerable Linux kernel versions that have not applied the patch. Since Linux is widely used across European enterprises, government agencies, and critical infrastructure, the vulnerability could potentially be exploited to execute arbitrary code or escalate privileges by manipulating the argument vector in execve() calls. Although no known exploits are currently in the wild, the demonstrated exploitability in related vulnerabilities (e.g., PwnKit) suggests that attackers could craft shellcode or malicious binaries that leverage this flaw to bypass security controls or gain unauthorized access. This could lead to confidentiality breaches, integrity violations, or availability disruptions if attackers execute malicious payloads or destabilize systems. The vulnerability affects the core kernel functionality, which underpins many Linux-based servers, desktops, and embedded devices. Therefore, unpatched systems in sectors such as finance, healthcare, manufacturing, and public administration could be at risk. The impact is heightened in environments where untrusted users have the ability to execute code or where automated processes invoke execve() with crafted arguments. However, the requirement for local code execution or user interaction to trigger the flaw somewhat limits the attack scope compared to remote vulnerabilities. Overall, the vulnerability poses a medium to high risk to European organizations depending on their Linux usage, patch management practices, and exposure to untrusted code execution.

To mitigate CVE-2022-49264 effectively, European organizations should: 1) Prioritize updating Linux kernels to versions that include the patch enforcing a single empty string in argv when empty, as this is the definitive fix. 2) Audit and review custom or legacy applications and scripts that invoke execve() or related exec functions to ensure they do not rely on empty argv behavior, which may break after patching. 3) Implement strict access controls and application whitelisting to limit the ability of untrusted users or processes to execute arbitrary binaries or scripts that could exploit this vulnerability. 4) Monitor system logs for warnings related to NULL argv usage, as the patched kernel emits WARN() messages in such cases, which can help identify problematic processes or potential exploitation attempts. 5) Employ runtime security tools such as Linux Security Modules (SELinux, AppArmor) or eBPF-based monitoring to detect anomalous execve() invocations or suspicious process creations. 6) Integrate this vulnerability into vulnerability management and patching cycles, ensuring timely deployment of kernel updates across all Linux systems, including embedded and IoT devices. 7) Educate developers and system administrators about the importance of proper argv handling and the risks associated with non-standard execve() usage to prevent recurrence of similar issues.