CVE-2026-86289
Received Received - Intake

Integer Overflow in Ollama GGUF Decoder

Publication date: 2026-09-07

Last updated on: 2026-09-07

Assigner: VulDB

Description
A vulnerability was found in Ollama up to 0.31.1. This issue affects the function readGGUFV1String of the file fs/ggml/gguf.go of the component GGUF Decoder. Performing a manipulation results in integer overflow. The attack is possible to be carried out remotely. The exploit has been made public and could be used. Upgrading to version 0.31.2-rc1 is capable of addressing this issue. The patch is named 67b6a1c2d45321e0cb3c04a18073f9818de7724b. It is recommended to upgrade the affected component.

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Meta Information

Published
2026-09-07
Last Modified
2026-09-07
Generated
2026-09-07
AI Q&A
2026-09-07
EPSS Evaluated
N/A
NVD
CVE-2026-86289
EUVD
EUVD-2026-72306

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
ollama ollama to 0.31.1 (inc)
ollama ollama to 0.31.2-rc1 (exc)
ollama ollama 0.31.2-rc1

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-189
CWE-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

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Executive Summary

This vulnerability is an integer overflow in the GGUF Decoder of Ollama up to version 0.31.1. It occurs in the readGGUFV1String function in the file fs/ggml/gguf.go. A manipulation of a zero-length string causes an unchecked Truncate operation to underflow, leading to a panic and denial-of-service (DoS) when decoding untrusted GGUF files.

Detection Guidance

Detecting this vulnerability requires checking the Ollama version installed on your system. Run 'ollama version' to verify if the version is below 0.31.2-rc1. Additionally, inspect GGUF model files for zero-length strings or malformed metadata that could trigger the integer overflow issue.

Impact Analysis

This vulnerability allows remote attackers to crash the Ollama service by providing a malicious GGUF model file. This results in a denial-of-service condition, making the service unavailable until restarted. It does not lead to memory corruption or data breaches.

Compliance Impact

This vulnerability, which causes integer overflow leading to denial-of-service (DoS) via malformed GGUF files, could impact compliance by disrupting service availability. For GDPR, availability is a key principle, and prolonged downtime may violate Article 32 requirements for security of processing. HIPAA also mandates availability of ePHI, so service disruption could pose compliance risks if systems handling protected data are affected.

Mitigation Strategies

Upgrade Ollama to version 0.31.2-rc1 or later immediately. Avoid processing untrusted GGUF model files until the update is applied. Monitor for crashes or errors when decoding models, as these may indicate exploitation attempts.

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