ZDI-26-403: (0Day) Ollama downloadBlob Improper Validation of Array Index Denial-of-Service Vulnerability
This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Ollama. Authentication is not required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.5. The following CVEs are assigned: CVE-2026-15685.
AI Analysis
Technical Summary
The Ollama product contains a vulnerability in its downloadBlob function where user-supplied data is not properly validated, leading to out-of-bounds memory access. This can be exploited remotely without authentication to trigger a denial-of-service condition, crashing or disrupting the service. The vulnerability has been assigned CVE-2026-15685 and a CVSS score of 7.5 by the Zero Day Initiative. No affected versions or patches have been disclosed. The advisory timeline shows coordinated disclosure with no vendor fix announced as of the advisory date.
Potential Impact
Remote attackers can cause a denial-of-service condition on affected Ollama installations by exploiting improper array index validation. This results in service disruption or crash, impacting availability. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
No official patch or fix has been announced. The advisory recommends restricting interaction with the affected product to mitigate the risk. Users should monitor vendor communications for updates on remediation.
ZDI-26-403: (0Day) Ollama downloadBlob Improper Validation of Array Index Denial-of-Service Vulnerability
Description
This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Ollama. Authentication is not required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.5. The following CVEs are assigned: CVE-2026-15685.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Ollama product contains a vulnerability in its downloadBlob function where user-supplied data is not properly validated, leading to out-of-bounds memory access. This can be exploited remotely without authentication to trigger a denial-of-service condition, crashing or disrupting the service. The vulnerability has been assigned CVE-2026-15685 and a CVSS score of 7.5 by the Zero Day Initiative. No affected versions or patches have been disclosed. The advisory timeline shows coordinated disclosure with no vendor fix announced as of the advisory date.
Potential Impact
Remote attackers can cause a denial-of-service condition on affected Ollama installations by exploiting improper array index validation. This results in service disruption or crash, impacting availability. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
No official patch or fix has been announced. The advisory recommends restricting interaction with the affected product to mitigate the risk. Users should monitor vendor communications for updates on remediation.
Technical Details
- Article Source
- {"url":"http://www.zerodayinitiative.com/advisories/ZDI-26-403/","fetched":true,"fetchedAt":"2026-07-09T11:08:24.823Z","wordCount":234}
- Classification
- {"confidence":0.95,"severitySource":"cvss-text","classifier":"rss-v2"}
Threat ID: 6a4f818768715ace4335a9ad
Added to database: 07/09/2026, 11:09:59 UTC
Last enriched: 07/31/2026, 01:42:03 UTC
Last updated: 08/23/2026, 12:23:00 UTC
Views: 123
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