CVE-2025-66960
📋 TL;DR
A vulnerability in ollama v0.12.10 allows remote attackers to cause denial of service by sending specially crafted GGUF files. The readGGUFV1String function fails to properly validate string length values from untrusted metadata, causing the application to panic and crash. This affects anyone running vulnerable ollama instances that process external GGUF files.
💻 Affected Systems
- ollama
📦 What is this software?
Ollama by Ollama
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption through repeated crashes, potentially leading to extended downtime if automated attacks target the service.
Likely Case
Intermittent service interruptions when malicious GGUF files are processed, requiring manual restart of ollama instances.
If Mitigated
Limited impact with proper input validation and monitoring, allowing quick detection and recovery from crashes.
🎯 Exploit Status
Proof of concept details are publicly available in the references. Creating malicious GGUF files requires understanding of the format but is straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v0.12.11 or later
Vendor Advisory: https://github.com/ollama/ollama/issues/9820
Restart Required: Yes
Instructions:
1. Stop ollama service. 2. Update ollama to v0.12.11 or later using your package manager or download from official sources. 3. Restart ollama service.
🔧 Temporary Workarounds
Restrict GGUF file sources
allOnly allow GGUF files from trusted sources and implement input validation for GGUF metadata
Implement rate limiting
allLimit the rate of GGUF file uploads/processing to reduce impact of repeated attacks
🧯 If You Can't Patch
- Implement network segmentation to isolate ollama instances from untrusted networks
- Deploy monitoring and automated restart mechanisms to detect and recover from crashes
🔍 How to Verify
Check if Vulnerable:
Check ollama version: ollama --version. If version is exactly 0.12.10, the system is vulnerable.Check Version:
ollama --versionVerify Fix Applied:
After updating, verify version is 0.12.11 or later: ollama --version📡 Detection & Monitoring
Log Indicators:
- Panic logs containing 'readGGUFV1String'
- Unexpected ollama process crashes
- Error messages related to GGUF parsing
Network Indicators:
- Multiple GGUF file uploads from single source in short time
- Unusual patterns in GGUF file processing requests
SIEM Query:
process.name:"ollama" AND (log_message:"panic" OR log_message:"readGGUFV1String" OR log_message:"GGUF")