CVE-2026-15685
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk31th percentile - higher than 31% of all known CVEs
Summary
A vulnerability in the downloadBlob function in Ollama allows a remote attacker to cause a denial-of-service (DoS) condition without authentication. The issue stems from improper validation of user-supplied data, leading to an out-of-bounds memory access.
Risk Assessment
An attacker can crash the Ollama system, disrupting service availability and potentially causing downtime for users.
Recommendation
Immediately update Ollama to the latest patched version. If not possible, restrict access to the service to trusted networks only.
Other vulnerabilities in Ollama
See all- CVE-2025-63389Critical
Critical authentication bypass vulnerability in Ollama platform's API endpoints up to v0.12.3. Multiple API endpoints are exposed without authentication, allowing remote attackers to perform unauthorized model management operations.
- CVE-2026-65315High
Ollama (HEAD f0078ae) has an uncontrolled memory allocation vulnerability in the GGUF metadata parser. A remote attacker can upload a crafted sub-1KB GGUF file via the blob upload and model create/pull APIs, triggering an unrecoverable Go runtime out-of-memory fatal error or makeslice panic that bypasses recovery middleware and crashes the entire server.
- CVE-2026-5757High
An unauthenticated remote attacker can read and exfiltrate the heap memory of the Ollama server through the model quantization engine, leading to sensitive data exposure.
- CVE-2026-5530Medium
Ollama up to version 0.18.1 contains a Server-Side Request Forgery (SSRF) vulnerability in the Model Pull API component (file server/download.go). An attacker can remotely manipulate the request, leading to requests being sent to internal resources.
- CVE-2025-15514High
Ollama versions 0.11.5-rc0 through 0.13.5 contain a null pointer dereference vulnerability in the multi-modal model image processing functionality. When processing base64-encoded image data via the /api/chat endpoint, the application fails to validate that the decoded data represents valid media before passing it to the mtmd_helper_bitmap_init_from_buf function. This function can return NULL for malformed input, but the code does not check this return value before dereferencing the pointer in subsequent operations.
Original NVD description (English source)
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.