CVE-2026-42249

Ollama for Windows contains a Remote Code Execution vulnerability in its update mechanism due to improper handling of attacker‑controlled HTTP response headers. When downloading updates, the application constructs local file paths using values derived from HTTP headers without validation. These values are passed directly to filepath.Join, allowing path traversal sequences (../) to be resolved and enabling files to be written outside the intended update staging directory. An attacker who can influence update responses can exploit this flaw to write arbitrary executables to attacker‑chosen locations accessible to the current user, including the Windows Startup directory. This allows execution of arbitrary executables. Critically, when chained with CVE‑2026‑42248 (Missing Signature Verification for Updates), an attacker can deliver malicious payloads that are written to sensitive locations and executed automatically. Because Ollama for Windows performs silent automatic updates and executes staged binaries without user interaction, this results in automatic and persistent code execution without user awareness. Maintainers of this project were notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Versions from 0.12.10 to 0.17.5 were tested and confirmed as vulnerable, other versions were not tested but might also be vulnerable.
References
Link Resource
https://cert.pl/en/posts/2026/04/CVE-2026-42248/ Third Party Advisory
https://ollama.com/ Product
Configurations

Configuration 1 (hide)

AND
cpe:2.3:a:ollama:ollama:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*

History

18 May 2026, 18:23

Type Values Removed Values Added
CPE cpe:2.3:a:ollama:ollama:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*
References () https://cert.pl/en/posts/2026/04/CVE-2026-42248/ - () https://cert.pl/en/posts/2026/04/CVE-2026-42248/ - Third Party Advisory
References () https://ollama.com/ - () https://ollama.com/ - Product
First Time Ollama ollama
Ollama
Microsoft windows
Microsoft
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 9.8

30 Apr 2026, 15:48

Type Values Removed Values Added
New CVE

Information

Published : 2026-04-29 12:16

Updated : 2026-06-17 10:47


NVD link : CVE-2026-42249

Mitre link : CVE-2026-42249

CVE.ORG link : CVE-2026-42249


JSON object : View

Products Affected

ollama

  • ollama

microsoft

  • windows
CWE
CWE-22

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CWE-494

Download of Code Without Integrity Check