CVE-2024-5991
📋 TL;DR
CVE-2024-5991 is an out-of-bounds read vulnerability in wolfSSL's X509 certificate hostname validation. Attackers can cause the library to read beyond allocated memory boundaries when processing non-NULL terminated hostname buffers. This affects all applications using wolfSSL versions through 5.7.0 for TLS/SSL certificate validation.
💻 Affected Systems
- wolfSSL
📦 What is this software?
Wolfssl by Wolfssl
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution or sensitive information disclosure through memory corruption leading to arbitrary code execution or data leakage.
Likely Case
Application crash (denial of service) or information disclosure from adjacent memory regions.
If Mitigated
Minimal impact with proper memory protections (ASLR, DEP) and input validation in calling applications.
🎯 Exploit Status
Exploitation requires control over certificate hostname validation input. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: wolfSSL 5.7.1
Vendor Advisory: https://github.com/wolfSSL/wolfssl/pull/7604
Restart Required: Yes
Instructions:
1. Download wolfSSL 5.7.1 or later from official repository. 2. Replace vulnerable wolfSSL installation. 3. Recompile and relink applications using wolfSSL. 4. Restart affected services.
🔧 Temporary Workarounds
Input validation wrapper
allImplement application-level validation to ensure hostname buffers are NULL terminated before calling X509_check_host()
// C code example: ensure buffer is NULL terminated
if (buffer[len-1] != '\0') { buffer[len] = '\0'; }
🧯 If You Can't Patch
- Implement strict input validation for all certificate hostname parameters
- Use network segmentation to isolate vulnerable systems from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check wolfSSL version: wolfSSL_lib_version() returns version string. Versions ≤5.7.0 are vulnerable.Check Version:
wolfSSL_lib_version() or check package manager: rpm -q wolfssl, dpkg -l libwolfsslVerify Fix Applied:
Verify wolfSSL version is ≥5.7.1 and check that MatchDomainName() properly validates buffer boundaries.📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory access violation errors in logs
Network Indicators:
- Unusual TLS handshake failures
- Abnormal certificate validation patterns
SIEM Query:
source="application_logs" AND ("segmentation fault" OR "memory violation" OR "out of bounds") AND process="*wolfssl*"