CVE-2026-42248
Missing Signature Verification for Updates in Ollama
Description
Ollama for Windows does not perform integrity or authenticity verification of downloaded update executables. Unlike other platforms, the Windows implementation of the update verification routine unconditionally returns success so no digital signature or trust validation is performed before staging or executing update payloads, enabling attacker‑supplied executables to be accepted and later executed by the application. Critically, Ollama for Windows performs silent automatic updates, so the malicious payload may be installed automatically 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.
INFO
Published Date :
April 29, 2026, 12:16 p.m.
Last Modified :
May 18, 2026, 6:22 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 4.0 | HIGH | 4bb8329e-dd38-46c1-aafb-9bf32bcb93c6 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Ensure Ollama for Windows performs signature validation.
- Update Ollama for Windows to the latest version.
- Verify update executables are trusted.
- Disable automatic updates if necessary.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42248.
| URL | Resource |
|---|---|
| https://cert.pl/en/posts/2026/04/CVE-2026-42248/ | Third Party Advisory |
| https://ollama.com/ | Product |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42248 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42248
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42248 vulnerability anywhere in the article.
-
The Hacker News
Ollama Out-of-Bounds Read Vulnerability Allows Remote Process Memory Leak
Cybersecurity researchers have disclosed a critical security vulnerability in Ollama that, if successfully exploited, could allow a remote, unauthenticated attacker to leak its entire process memory. ... Read more
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cert.pl
Vulnerabilities in Ollama software
Vulnerabilities in Ollama software CVE ID CVE-2026-42248 Publication date 29 April 2026 Vendor Ollama Product Ollama Vulnerable versions From 0.12.10 through 0.17.5 Vulnerability type (CWE) Download o ... Read more
The following table lists the changes that have been made to the
CVE-2026-42248 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
May. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Added CPE Configuration AND OR *cpe:2.3:a:ollama:ollama:*:*:*:*:*:*:*:* versions from (including) 0.12.10 up to (including) 0.17.5 OR cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:* Added Reference Type CERT.PL: https://cert.pl/en/posts/2026/04/CVE-2026-42248/ Types: Third Party Advisory Added Reference Type CERT.PL: https://ollama.com/ Types: Product -
New CVE Received by [email protected]
Apr. 29, 2026
Action Type Old Value New Value Added Description Ollama for Windows does not perform integrity or authenticity verification of downloaded update executables. Unlike other platforms, the Windows implementation of the update verification routine unconditionally returns success so no digital signature or trust validation is performed before staging or executing update payloads, enabling attacker‑supplied executables to be accepted and later executed by the application. Critically, Ollama for Windows performs silent automatic updates, so the malicious payload may be installed automatically 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. Added CVSS V4.0 AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-494 Added Reference https://cert.pl/en/posts/2026/04/CVE-2026-42248/ Added Reference https://ollama.com/