CVE-2025-59777
📋 TL;DR
A NULL pointer dereference vulnerability in GNU libmicrohttpd v1.0.2 and earlier allows attackers to cause denial-of-service (DoS) by sending specially crafted packets. This affects any application using vulnerable versions of libmicrohttpd as an embedded HTTP server library. The vulnerability can crash the server process, disrupting service availability.
💻 Affected Systems
- GNU libmicrohttpd
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service outage with server process crash, requiring manual restart and potentially causing data loss or service disruption.
Likely Case
Service disruption through server crashes, requiring restart of affected applications using libmicrohttpd.
If Mitigated
Minimal impact if proper network segmentation and monitoring are in place to detect and respond to crashes quickly.
🎯 Exploit Status
Exploitation requires sending specially crafted packets to the HTTP server, which is straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Master branch after commit ff13abc1c1d7d2b30d69d5c0bd4a237e1801c50b
Vendor Advisory: https://www.gnu.org/software/libmicrohttpd/
Restart Required: Yes
Instructions:
1. Update to libmicrohttpd from master branch after commit ff13abc1c1d7d2b30d69d5c0bd4a237e1801c50b. 2. Rebuild and redeploy any applications using libmicrohttpd. 3. Restart affected services.
🔧 Temporary Workarounds
Network filtering
allImplement network filtering to block malicious HTTP requests at firewall or load balancer level.
Process monitoring and auto-restart
linuxConfigure process monitoring to automatically restart crashed libmicrohttpd instances.
systemctl enable your-service
systemctl start your-service
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to trusted sources only.
- Deploy intrusion detection systems to monitor for DoS attempts and anomalous traffic patterns.
🔍 How to Verify
Check if Vulnerable:
Check libmicrohttpd version in your application dependencies or system packages. If version is 1.0.2 or earlier, you are vulnerable.Check Version:
ldd --version | grep libmicrohttpd or check application dependency manifestVerify Fix Applied:
Verify that libmicrohttpd is built from source after commit ff13abc1c1d7d2b30d69d5c0bd4a237e1801c50b or check version string if a new release is available.📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes or segmentation faults in applications using libmicrohttpd
- Abnormal termination logs with NULL pointer references
Network Indicators:
- Spike in malformed HTTP requests to libmicrohttpd endpoints
- Unusual traffic patterns from single sources
SIEM Query:
source="application.logs" AND ("segmentation fault" OR "null pointer" OR "libmicrohttpd crash")