CVE-2026-0861
📋 TL;DR
An integer overflow vulnerability in GNU C Library's memalign functions (memalign, posix_memalign, aligned_alloc) can lead to heap corruption when both size and alignment parameters are attacker-controlled. This affects applications using glibc versions 2.30 through 2.42. Exploitation requires specific conditions where alignment values are unusually large and size parameters approach system limits.
💻 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
Heap corruption leading to arbitrary code execution, privilege escalation, or system compromise if an attacker controls both size and alignment parameters.
Likely Case
Application crash or denial of service due to heap corruption; remote code execution is possible but requires specific application conditions.
If Mitigated
Minimal impact since alignment parameters are typically constrained values not under attacker control in most applications.
🎯 Exploit Status
Exploitation requires attacker control over both size and alignment parameters, with alignment in specific ranges (≥1<<62+1 for memalign, exactly 1<<63 for posix_memalign/aligned_alloc).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: glibc 2.43 or later
Vendor Advisory: https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0001
Restart Required: Yes
Instructions:
1. Update glibc to version 2.43 or later. 2. For distributions: Use package manager (apt-get upgrade libc6, yum update glibc, etc.). 3. Restart affected services or reboot system.
🔧 Temporary Workarounds
Input validation for alignment parameters
linuxValidate alignment parameters in application code to ensure they're within safe ranges before passing to memalign functions.
🧯 If You Can't Patch
- Review application code to ensure alignment parameters aren't derived from untrusted input
- Implement runtime monitoring for unusual alignment values in memalign function calls
🔍 How to Verify
Check if Vulnerable:
Check glibc version: ldd --version | grep 'ldd' or check /lib/x86_64-linux-gnu/libc.so.6Check Version:
ldd --version | head -1Verify Fix Applied:
Verify glibc version is 2.43 or later after update📡 Detection & Monitoring
Log Indicators:
- Application crashes with heap corruption errors
- Unusual memory allocation patterns
SIEM Query:
Search for process crashes involving libc memory allocation functions or unusual alignment parameter values