Integer Overflow Vulnerability in Ollama GGUF Decoder
CVE-2026-86289

5.3MEDIUM

Key Information:

Vendor: Ollama
Status: Ollama
Vendor: CVE Published:; 7 September 2026

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👾 Exploit Exists🟡 Public PoC

What is CVE-2026-86289?

A vulnerability has been identified in the Ollama GGUF Decoder, affecting versions up to 0.31.1. This issue arises from the function readGGUFV1String located in the file fs/ggml/gguf.go. An integer overflow can be triggered through remote manipulation. The exploit details have been made public, highlighting the urgency of addressing this security loophole. Users are advised to upgrade to version 0.31.2-rc1, which includes the necessary patch to mitigate this risk. The patch is identified by the commit hash 67b6a1c2d45321e0cb3c04a18073f9818de7724b.

Affected Version(s)

Ollama 0.31.0

Ollama 0.31.1

Ollama 0.31.2-rc1

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-86289 - Proof of Concept