CVE-2026-42249 Remote Code Execution in Ollama via Update Mechanism
Attackers can achieve remote code execution on Windows by exploiting path traversal in the update mechanism to write and execute arbitrary files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42249?
CVE-2026-42249 is a high-severity path traversal vulnerability in Ollama, published on 29 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-42249?
It affects 1 product.
Products include Ollama Ollama.
How do I fix CVE-2026-42249?
No fix published yet.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-42249 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42249 exists.
Public exploit code: 1 Metasploit module.
Other vulnerabilities in Ollama
- CVE-2025-63389 Ollama Platform has missing authentication enabling attackers to perform model management operations
- CVE-2024-45436 Ollama can extract members of a ZIP archive outside of the parent directory
- CVE-2026-7482 Ollama heap out-of-bounds read in GGUF tensor parsing leaks server process memory to unauthenticated remote attackers
- CVE-2024-37032 Ollama does not validate the format of the digest (sha256 with 64 hex digits)
- CVE-2025-15514 Ollama Multi-Modal Model Image Processing NULL Pointer Dereference
Sources
Also known as GHSA-7mp6-jmch-f3fh, MINI-7f2f-9rfm-gr2w.