CVE-1999-0371 is a vulnerability in the Lynx text-based web browser that allows a local user to overwrite sensitive files via symbolic links in the /tmp directory. Specifically, the vulnerability arises because Lynx improperly handles temporary files, enabling an attacker with local access to create symlinks in /tmp that point to sensitive system files. When Lynx writes to these temporary files, it inadvertently overwrites the target files pointed to by the symlinks. This can lead to partial disclosure or modification of sensitive files, potentially impacting system integrity or confidentiality. The vulnerability requires local access and is not remotely exploitable. It also has a high attack complexity, meaning exploitation is non-trivial and requires specific conditions. The CVSS score is low (1.2), reflecting limited impact and difficulty of exploitation. No patches are available, and there are no known exploits in the wild. Given the age of the vulnerability (published in 1999), modern Lynx versions and operating systems likely have mitigations or have addressed this issue, but legacy systems or outdated Lynx installations may remain vulnerable.

For European organizations, the impact of this vulnerability is generally low due to its requirement for local access and the high complexity of exploitation. However, in environments where Lynx is still used—such as legacy systems, specialized embedded devices, or certain research or educational institutions—there is a risk that a malicious insider or an attacker who has gained limited local access could leverage this vulnerability to overwrite sensitive files. This could lead to data corruption, privilege escalation, or disruption of critical services if important configuration or system files are targeted. The confidentiality impact is partial, as the vulnerability primarily allows file overwriting rather than direct data disclosure. The integrity of affected files is at risk, but availability impact is minimal. European organizations with strict data protection regulations (e.g., GDPR) should be cautious about any vulnerability that could lead to unauthorized file modifications, even if the risk is low. Overall, the threat is more relevant in controlled internal environments rather than from external attackers.

To mitigate this vulnerability, European organizations should: 1) Ensure that Lynx installations are updated to the latest available versions where this issue has been addressed or mitigated. 2) Restrict local user access on systems running Lynx to trusted personnel only, minimizing the risk of malicious local exploitation. 3) Implement strict file system permissions and monitoring on the /tmp directory to detect and prevent unauthorized creation of symbolic links that could be used for exploitation. 4) Consider using alternative browsers or tools if Lynx is not essential, especially on critical systems. 5) Employ security best practices such as mandatory access controls (e.g., SELinux, AppArmor) to limit the ability of processes to overwrite sensitive files via symlinks. 6) Regularly audit and monitor system logs for suspicious activity related to temporary file handling. Since no patches are available, these compensating controls are essential to reduce risk.