CVE-2025-4802
📋 TL;DR
This vulnerability in GNU C Library (glibc) versions 2.27 to 2.38 allows attackers to load malicious shared libraries via the LD_LIBRARY_PATH environment variable in statically compiled setuid binaries. This can lead to privilege escalation when attackers can execute such binaries. Systems using affected glibc versions with setuid binaries are vulnerable.
💻 Affected Systems
- GNU C Library (glibc)
📦 What is this software?
Glibc by Gnu
The GNU C Library (glibc) is the core C library for Linux systems, providing essential system calls and basic functions for all C programs. It is a fundamental component that nearly every Linux application depends on.
Learn more about Glibc →⚠️ Risk & Real-World Impact
Worst Case
Full root privilege escalation on affected systems through exploitation of vulnerable setuid binaries, leading to complete system compromise.
Likely Case
Local privilege escalation allowing attackers to gain elevated privileges on systems where they have user access and vulnerable setuid binaries exist.
If Mitigated
No impact if proper security controls prevent untrusted users from executing setuid binaries or if systems are patched.
🎯 Exploit Status
Exploitation requires local access to execute vulnerable setuid binaries. Proof-of-concept code is publicly available in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: glibc 2.39 or patched versions from distributions
Vendor Advisory: https://sourceware.org/bugzilla/show_bug.cgi?id=32976
Restart Required: Yes
Instructions:
1. Update glibc package from your distribution's repositories. 2. For Debian/Ubuntu: apt update && apt upgrade libc6. 3. For RHEL/CentOS: yum update glibc. 4. Reboot system to ensure all processes use updated library.
🔧 Temporary Workarounds
Remove LD_LIBRARY_PATH from setuid environment
linuxConfigure system to strip LD_LIBRARY_PATH from environment of setuid programs
echo 'LD_LIBRARY_PATH' >> /etc/suid-debug
Disable vulnerable setuid binaries
linuxRemove setuid bit from potentially vulnerable binaries
chmod u-s /path/to/binary
🧯 If You Can't Patch
- Restrict access to setuid binaries using filesystem permissions
- Implement strict user privilege separation and limit shell access
🔍 How to Verify
Check if Vulnerable:
Check glibc version with: ldd --version | head -1Check Version:
ldd --version | head -1Verify Fix Applied:
Verify glibc version is 2.39 or higher, or check with distribution-specific security updates📡 Detection & Monitoring
Log Indicators:
- Failed privilege escalation attempts
- Unusual library loading in setuid context
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
process.name contains "setuid" AND process.env contains "LD_LIBRARY_PATH"🔗 References
- https://sourceware.org/bugzilla/show_bug.cgi?id=32976
- https://sourceware.org/cgit/glibc/commit/?id=1e18586c5820e329f741d5c710275e165581380e
- http://www.openwall.com/lists/oss-security/2025/05/16/7
- http://www.openwall.com/lists/oss-security/2025/05/17/2
- https://lists.debian.org/debian-lts-announce/2025/05/msg00033.html
