CVE-2026-84243

A flaw was found in glibc. The library's localization functions fail to properly sanitize directory traversal characters within the LANGUAGE environment variable. A local attacker capable of setting this variable across trust boundaries can force a target program to load a malicious translation file from an arbitrary filesystem location. This issue can lead to arbitrary code execution under the privileges of the running application or cause an application crash, resulting in a denial of service (DoS).

This vulnerability is rated as Moderate impact because privilege boundaries protected by AT_SECURE, such as setuid and setgid binaries, are inherently not affected. Exploitation requires multiple specific preconditions, including the ability to write a crafted message file to the system and control environment variables across a non-setuid trust boundary (such as through SSH forced command configurations accepting client locales). Under standard Red Hat Enterprise Linux configurations, users able to set their own process environment already run with identical privileges to those of the executed binary, significantly limiting scenarios for unauthorized escalation.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.