CVE-2025-34468
📋 TL;DR
A stack-based buffer overflow vulnerability in libcoap allows remote attackers to crash applications or potentially execute arbitrary code when proxy functionality is enabled. This affects all libcoap versions up to 4.3.5. Applications using libcoap with proxy request handling enabled are vulnerable to exploitation.
💻 Affected Systems
- libcoap
📦 What is this software?
Libcoap by Libcoap
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or persistent backdoor installation.
Likely Case
Denial of service through application crashes, with potential for limited code execution depending on memory protections.
If Mitigated
Application crash without code execution if ASLR, stack canaries, or other memory protections are enabled.
🎯 Exploit Status
Exploitation requires proxy functionality to be enabled and attacker-controlled hostname data.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: libcoap after commit 30db3ea
Vendor Advisory: https://github.com/obgm/libcoap/commit/30db3ea
Restart Required: Yes
Instructions:
1. Update libcoap to version after commit 30db3ea. 2. Rebuild applications using libcoap. 3. Restart affected services.
🔧 Temporary Workarounds
Disable Proxy Functionality
allDisable proxy request handling in applications using libcoap to prevent exploitation.
Configure application to disable COAP_PROXY feature
🧯 If You Can't Patch
- Disable proxy functionality in all applications using libcoap
- Implement network segmentation to isolate vulnerable systems
🔍 How to Verify
Check if Vulnerable:
Check libcoap version and verify if proxy functionality is enabled in applications.Check Version:
ldconfig -p | grep libcoapVerify Fix Applied:
Verify libcoap version is after commit 30db3ea and test proxy functionality.📡 Detection & Monitoring
Log Indicators:
- Application crashes, segmentation faults, abnormal termination of libcoap processes
Network Indicators:
- Unusual CoAP traffic to proxy-enabled endpoints, malformed hostname data in requests
SIEM Query:
process:terminated AND (libcoap OR coap) AND (segfault OR crash)