rajasingh010/ollama-gguf-dos-1

GGUF readArrayData() Unbounded Memory Allocation — DoS PoC

WARNING: MALICIOUS FILE — SECURITY RESEARCH ONLY

Vulnerability

File: fs/gguf/gguf.go Function: readArrayData() Type: Denial of Service (Unbounded Memory Allocation / OOM)

Description

Ollama's Go GGUF parser has no upper bound check on array length in readArrayData(). When reading array metadata, make([]T, n) is called with a uint64 n from the file, without validating that n is within reasonable bounds.

func readArrayData[T any](f *File, n uint64) (s []T, err error) {
    s = make([]T, n)  // n attacker-controlled, no bounds check
    ...
}

With array_length = 0x100000000 (2^32) and uint64 elements:

• 2^32 × 8 bytes = 32 GB allocation attempt → OOM panic → service crash

Impact

• Severity: High (CVSS 7.5)
• Attack Vector: Upload malicious GGUF to Ollama server → OOM crash
• Authentication: None required (unauthenticated API endpoint)
• Affected Versions: Ollama with Go GGUF parser (all versions prior to patch)

Reproduction

# Upload malicious GGUF
curl -X POST http://localhost:11434/api/create -d @malicious_gguf_array_overflow.gguf

# Result: OOM panic → service crash

Fix

func readArrayData[T any](f *File, n uint64) (s []T, err error) {
    if n > 1<<20 {  // limit to ~1M elements
        return nil, errors.New("array length exceeds limit")
    }
    s = make([]T, n)
    ...
}

References

• https://huntr.com/repos/ollama/ollama