CVE-2025-14017
📋 TL;DR
CVE-2025-14017 is a thread safety vulnerability in libcurl's LDAPS implementation where TLS option changes in one thread affect all concurrent LDAPS transfers globally. This allows disabling certificate verification for one transfer to unintentionally disable verification for other threads, potentially enabling man-in-the-middle attacks. Affects applications using libcurl for multi-threaded LDAPS connections.
💻 Affected Systems
- libcurl
- curl
- applications using libcurl for LDAPS
📦 What is this software?
Curl by Haxx
curl is a command-line tool and library for transferring data with URLs. It supports numerous protocols including HTTP, HTTPS, FTP, and more, making it essential for API testing, web scraping, and automated data transfers.
Learn more about Curl →⚠️ Risk & Real-World Impact
Worst Case
Attackers could perform man-in-the-middle attacks against LDAPS connections, intercepting or modifying sensitive LDAP data including authentication credentials and directory information.
Likely Case
Accidental misconfiguration where disabling certificate verification for one transfer unintentionally disables it for others, potentially exposing sensitive LDAP queries to interception.
If Mitigated
Limited impact if proper network segmentation and certificate validation are already enforced at network level.
🎯 Exploit Status
Exploitation requires ability to control TLS options in one thread while other threads are performing LDAPS transfers. This typically requires application-level access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: libcurl 8.10.0
Vendor Advisory: https://curl.se/docs/CVE-2025-14017.html
Restart Required: Yes
Instructions:
1. Identify applications using libcurl
2. Update libcurl to version 8.10.0 or later
3. Recompile applications if using static linking
4. Restart affected services
🔧 Temporary Workarounds
Disable multi-threaded LDAPS
allConfigure applications to use single-threaded LDAPS connections or avoid LDAPS entirely
Application-specific configuration required
Enforce certificate verification at application level
allImplement additional certificate validation logic in application code
Application-specific implementation required
🧯 If You Can't Patch
- Isolate LDAPS connections to trusted networks only
- Implement network-level TLS inspection and certificate validation
🔍 How to Verify
Check if Vulnerable:
Check libcurl version: curl --version | grep libcurlCheck Version:
curl --version | grep libcurlVerify Fix Applied:
Verify libcurl version is 8.10.0 or higher: curl --version | grep libcurl📡 Detection & Monitoring
Log Indicators:
- LDAPS connection failures
- Certificate validation errors
- Unexpected LDAP query results
Network Indicators:
- Unencrypted LDAP traffic after LDAPS initiation
- Suspicious certificate changes during LDAPS sessions
SIEM Query:
source="*ldap*" AND (event="certificate_error" OR event="tls_error")