CVE-2025-4802: GNU Glibc LD_LIBRARY_PATH RCE Vulnerability

CVE-2025-4802 Overview

Untrusted LD_LIBRARY_PATH environment variable vulnerability in the GNU C Library versions 2.27 to 2.38 allows attacker-controlled loading of dynamically shared library in statically compiled setuid binaries that call dlopen (including internal dlopen calls after setlocale or calls to NSS functions such as getaddrinfo).

Critical Impact

This vulnerability allows local attackers to execute arbitrary code with elevated privileges in certain scenarios where LD_LIBRARY_PATH manipulation is possible.

Affected Products

• gnu glibc

Discovery Timeline

• Not Available - Vulnerability discovered by Not Available
• Not Available - Responsible disclosure to gnu
• Not Available - CVE CVE-2025-4802 assigned
• Not Available - gnu releases security patch
• 2025-05-16 - CVE CVE-2025-4802 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-4802

Vulnerability Analysis

The issue arises due to improper validation of the LD_LIBRARY_PATH environment variable in statically compiled setuid binaries. When such binaries call dlopen, they can inadvertently load malicious shared libraries specified by an untrusted LD_LIBRARY_PATH provided by an attacker.

Root Cause

The root cause of this vulnerability is the reliance on environment variables without adequate validation, allowing manipulation by local attackers to gain unauthorized access.

Attack Vector

Local attackers can manipulate the LD_LIBRARY_PATH to direct vulnerable binaries to load malicious libraries, leading to arbitrary code execution.

// Example exploitation code (sanitized)
#include <stdlib.h>

int main() {
    setenv("LD_LIBRARY_PATH", "/attacker/controlled/path", 1);
    system("/path/to/vulnerable/binary");
    return 0;
}

Detection Methods for CVE-2025-4802

Indicators of Compromise

• Unexpected setuid binary behavior
• Presence of unexpected libraries in /attacker/controlled/path
• Logs indicating library loads from non-standard paths

Detection Strategies

Security teams should monitor for unusual LD_LIBRARY_PATH settings in user environments and correlate these with execution of setuid binaries.

Monitoring Recommendations

• Implement key logging for changes to the LD_LIBRARY_PATH
• Audit logs for execution of sensitive binaries in user sessions
• Use integrity checking tools to monitor changes in library loading paths

How to Mitigate CVE-2025-4802

Immediate Actions Required

• Validate environment variables before use in binaries
• Utilize statically linked binaries without dlopen dependencies
• Restrict access to environment variable setting mechanisms

Patch Information

Update to the latest version of glibc as available from the vendor resources outlined in Gnu Advisory.

Workarounds

Restrict usage of LD_LIBRARY_PATH by ensuring that vulnerable applications do not execute under circumstances where the environment can be controlled by potentially malicious users.

# Configuration example
unset LD_LIBRARY_PATH
export LD_LIBRARY_PATH=/usr/lib