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 specific flaw exists within the downloadBlob function. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated array. An attacker can leverage this vulnerability to create a denial-of-service condition on the system.
Other sources
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.
— ZDI
Affected Software
Event History
Frequently Asked Questions
What is the severity of ZDI-26-403?
The severity of ZDI-26-403 is high, rated at 7.5.
How do I fix ZDI-26-403?
To fix ZDI-26-403, ensure you update to the latest version of Ollama where the vulnerability is patched.
What type of vulnerability is ZDI-26-403?
ZDI-26-403 is an improper validation of array index vulnerability that leads to a denial-of-service condition.
Does ZDI-26-403 require authentication to exploit?
No, ZDI-26-403 does not require authentication to be exploited by attackers.
What specific function is affected by ZDI-26-403?
The specific function affected by ZDI-26-403 is the downloadBlob function within Ollama.