Vulnerability · Published Jul 13, 2026 · Assigned by zdi

CVE-2026-15685Ollama downloadBlob Improper Validation of Array Index Denial-of-Service Vulnerability

High 7.5

In plain English

A high-severity security flaw in Ollama from Ollama. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities).

Severity (CVSS 3.0)7.5High

Exploit odds (30 days)0.7%top 46.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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. Was ZDI-CAN-27277.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	ollama	no fix listed	PYSEC-2026-3450

Affected products (as reported)

Vendor	Product	Versions
Ollama	Ollama	0.7.1

Weakness: CWE-129 · Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

ZDI-26-403 x_research-advisory