CVE-2025-14831
📋 TL;DR
A denial-of-service vulnerability in GnuTLS allows attackers to cause excessive CPU and memory consumption by presenting malicious certificates with numerous name constraints and subject alternative names. This affects systems using GnuTLS for TLS/SSL certificate validation, potentially impacting web servers, VPNs, and other TLS-dependent services.
💻 Affected Systems
- GnuTLS
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to resource exhaustion, potentially affecting multiple services on the same host.
Likely Case
Degraded performance or temporary service interruptions for TLS-handling applications.
If Mitigated
Minimal impact with proper resource limits and monitoring in place.
🎯 Exploit Status
Exploitation requires presenting malicious certificates to vulnerable systems.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor-specific updates (e.g., Red Hat, Debian, Ubuntu).
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2025-14831
Restart Required: Yes
Instructions:
1. Check your distribution's security advisories. 2. Update GnuTLS package via package manager. 3. Restart affected services using GnuTLS.
🔧 Temporary Workarounds
Limit certificate processing resources
linuxConfigure system resource limits (e.g., CPU, memory) for processes using GnuTLS to mitigate DoS impact.
ulimit -v <memory_limit>
systemctl set-property <service> CPUQuota=<percentage>%
🧯 If You Can't Patch
- Implement network filtering to block or rate-limit untrusted certificate sources.
- Monitor system resources and set alerts for abnormal CPU/memory usage in TLS-handling processes.
🔍 How to Verify
Check if Vulnerable:
Check GnuTLS version against vendor advisories; command: gnutls-cli --versionCheck Version:
gnutls-cli --version | head -1Verify Fix Applied:
Verify updated GnuTLS version matches patched release from vendor.📡 Detection & Monitoring
Log Indicators:
- High CPU/memory usage logs from TLS-handling processes
- Failed TLS handshake logs with certificate errors
Network Indicators:
- Unusual spikes in TLS handshake attempts from single sources
SIEM Query:
source="system_logs" (process="gnutls" OR service="tls") AND (cpu_usage>90 OR memory_usage>90)