CVE-2000-0270 is a vulnerability found in GNU Emacs versions 20.0 through 20.6, specifically in the make-temp-name Lisp function. This function is responsible for creating temporary files during Emacs operations. The issue arises because the temporary files are created with predictable names, which can be anticipated by an attacker. This predictability enables a symlink attack, where an attacker creates a symbolic link with the expected temporary filename pointing to a sensitive file. When Emacs writes to the temporary file, it inadvertently overwrites or modifies the target file linked by the symlink. This can lead to unauthorized modification of files, potentially compromising data integrity and confidentiality. The vulnerability requires local access (AV:L) and no authentication (Au:N), with low attack complexity (AC:L). The CVSS score is 3.6, indicating a low severity level. There are no known exploits in the wild, and no patches are available for these older Emacs versions, which are now considered legacy software.

For European organizations, the impact of this vulnerability is generally limited due to the requirement for local access and the absence of remote exploitation capabilities. However, in environments where Emacs 20.x is still in use—such as legacy systems, academic institutions, or specialized development environments—this vulnerability could allow an attacker with local access to manipulate or corrupt files by exploiting predictable temporary file names. This could lead to data integrity issues, unauthorized data modification, or potential privilege escalation if critical configuration or system files are targeted. While the confidentiality impact is partial, the integrity impact is more significant. The lack of availability impact reduces the overall risk. Given the age of the vulnerability and the software versions affected, the threat is mostly relevant in niche or legacy contexts rather than widespread modern enterprise environments.

Since no official patches are available for Emacs 20.x, European organizations should consider the following specific mitigations: 1) Upgrade to a more recent and actively maintained version of Emacs where this vulnerability has been addressed. 2) If upgrading is not immediately possible, restrict local access to systems running vulnerable Emacs versions to trusted users only, minimizing the risk of local exploitation. 3) Implement file system monitoring to detect unexpected symbolic links or changes in directories where temporary files are created by Emacs. 4) Use operating system-level security features such as mandatory access controls (e.g., SELinux, AppArmor) to limit the ability of users to create symbolic links in sensitive directories. 5) Educate users and administrators about the risks of using outdated software and encourage migration to supported versions. 6) Consider running Emacs in a sandboxed environment or container to limit the scope of potential damage from exploitation.