Vulnerability · Published Sep 7, 2026 · Assigned by VulDB

CVE-2026-86289Ollama GGUF Decoder gguf.go readGGUFV1String integer overflow

Medium 4.3

In plain English

A medium-severity integer overflow in Ollama. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)0.7%top 47.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
n/a	Ollama	0.31.00.31.1

Weakness: CWE-190, CWE-189 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C

References

VDB-399448 | Ollama GGUF Decoder gguf.go readGGUFV1String integer overflow vdb-entry, technical-description
VDB-399448 | CTI Indicators (IOB, IOC, IOA) signature, permissions-required
CVE-2026-86289 | CVE Analysis and Report third-party-advisory
Submit #906136 | Ollama <= 0.17.1 Integer Overflow third-party-advisory
https://github.com/ollama/ollama/issues/17033 exploit, issue-tracking
https://github.com/ollama/ollama/pull/17062 issue-tracking, patch
https://github.com/ollama/ollama/commit/67b6a1c2d45321e0cb3c04a18073f9818de7724b patch
https://github.com/ollama/ollama/releases/tag/v0.31.2-rc1 patch
https://github.com/ollama/ollama/ product