CVE-2026-86289 Ollama CVE debrief

Who should care

Defenders responsible for Ollama deployments should assess exposure to this vulnerability and prioritize verification and potential upgrades. This includes operators managing Ollama instances, platform administrators, vulnerability management teams, and security teams that need to evaluate the risk and implement necessary mitigations.

Why it matters

Defenders should prioritize verifying exposure of Ollama deployments to this vulnerability and assess the potential impact of an integer overflow in the GGUF Decoder component.

• Verification of Ollama deployments for exposure to this vulnerability
• Potential impact assessment of an integer overflow in the GGUF Decoder component
• Upgrade to version 0.31.2-rc1 or later to address the issue
• Monitoring for potential exploitation attempts

Technical summary

The vulnerability affects the function readGGUFV1String of the file fs/ggml/gguf.go of the component GGUF Decoder in Ollama up to version 0.31.1. An integer overflow occurs when a manipulation is performed. The attack can be carried out remotely. Defenders should prioritize verifying exposure of Ollama deployments to this vulnerability and assess the potential impact of an integer overflow in the GGUF Decoder component. The CVE record and NVD entry provide details on the vulnerability, including its description, affected versions, and patch information.

Defensive priority

Defenders should prioritize verifying exposure of Ollama deployments to this vulnerability and assess the potential impact of an integer overflow in the GGUF Decoder component.

Recommended defensive actions

• Verify Ollama deployments for exposure to this vulnerability
• Assess the potential impact of an integer overflow in the GGUF Decoder component
• Upgrade to version 0.31.2-rc1 or later
• Monitor for potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, affected versions, and patch information. However, there is limited information on potential exploitation or victim impact.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.