CVE-2022-45939 is a high-severity command injection vulnerability affecting GNU Emacs through version 28.2, specifically within the implementation of the ctags program located in lib-src/etags.c. The vulnerability arises because the ctags program uses the system C library function to execute shell commands without properly sanitizing input, particularly the names of source-code files. An attacker can exploit this by placing specially crafted filenames containing shell metacharacters in a directory. When a user runs the "ctags *" command, which is commonly suggested in the ctags documentation, the shell interprets these metacharacters, allowing arbitrary command execution. This can lead to full compromise of the user environment running the command. The vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command), highlighting its nature as a command injection flaw. The CVSS v3.1 base score is 7.8, reflecting high severity, with an attack vector of local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The impact on confidentiality, integrity, and availability is high, as arbitrary commands can be executed with the privileges of the user running ctags. No known exploits in the wild have been reported, and no official patches are linked in the provided data, indicating that mitigation may rely on workarounds or updates from GNU Emacs maintainers. This vulnerability primarily affects users who run ctags commands in directories containing untrusted or attacker-controlled filenames, which is a common scenario in development environments or automated build systems.

For European organizations, the impact of CVE-2022-45939 can be significant, especially in software development, research, and academic institutions where GNU Emacs and ctags are widely used. Successful exploitation can lead to arbitrary code execution, resulting in potential data breaches, unauthorized access to sensitive source code, and disruption of development workflows. Since the vulnerability requires local access and user interaction, insider threats or compromised user accounts could leverage this flaw to escalate privileges or move laterally within networks. The high impact on confidentiality, integrity, and availability means that critical intellectual property and operational continuity could be at risk. Additionally, automated build systems or continuous integration pipelines that invoke ctags on untrusted directories could be compromised, affecting software supply chain security. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as proof-of-concept exploits may emerge. Organizations relying on GNU Emacs for development should consider this vulnerability seriously to prevent potential exploitation.

1. Avoid running the "ctags *" command or any ctags invocation in directories containing untrusted or attacker-controlled filenames. 2. Sanitize or validate filenames in source directories before running ctags to ensure they do not contain shell metacharacters or malicious payloads. 3. Use alternative tagging tools or updated versions of ctags that do not rely on vulnerable system calls until a patch is released. 4. Run ctags commands with the least privilege necessary, ideally in isolated or sandboxed environments to limit potential damage from exploitation. 5. Monitor and restrict local user access to development environments where GNU Emacs and ctags are used, reducing the risk of insider threats. 6. Implement file integrity monitoring on source directories to detect unexpected or suspicious filename changes. 7. Stay updated with GNU Emacs security advisories and apply patches promptly once available. 8. Educate developers and system administrators about the risks of executing commands in directories with untrusted content and encourage secure operational practices.