CVE-2026-42248: Ollama for Windows does not perform integrity or authenticity verification of downloaded update executables

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-42248 is a critical-severity flaw (CVSS 9.8) affecting ollama. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 Wind

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 46%)
CISA exploited list	No
Weakness	CWE-494
Published	2026-04-29
Last modified	2026-06-17

Publisher (CNA): CERT.PL · Vendor: ollama

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-29 12:16 UTCPublished CVE record published
2026-06-17 10:47 UTCUpdated Record last modified

ollama ollama UPGRADE

Affected: >= 0.12.10 and <= 0.17.5

Fixed in: newer than 0.17.5

Safe to downgrade to: a release before 0.12.10

1. Check installed version

apt-cache policy ollama || rpm -q ollama || ollama --version

2. UPGRADE to newer than 0.17.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ollama

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ollama

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.12.10 (Debian / Ubuntu)

apt-cache madison ollama sudo apt install ollama=<VERSION_BEFORE_0.12.10> sudo apt-mark hold ollama

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ollama sudo dnf downgrade ollama-<VERSION_BEFORE_0.12.10> sudo dnf versionlock add ollama

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

Fedora 46 · python-python-ulid · FIXED · 4.1.0-2.fc46 · FEDORA-2026-3652e4825b · source

sudo dnf upgrade --advisory=FEDORA-2026-3652e4825b

Fedora ELN · gmp · FIXED · 6.3.0-7.eln159 · FEDORA-2026-1139089b36 · source

sudo dnf upgrade --advisory=FEDORA-2026-1139089b36

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Metasploit: Ollama Windows Auto-Update Path Traversal Persistence

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-42248?

ollama: upgrade to newer than 0.17.5. Exact commands for each OS are on this page.

Is CVE-2026-42248 being exploited?

CVE-2026-42248 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-42248 affect?

CVE-2026-42248 affects ollama. Severity is critical (CVSS 9.8). 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

How urgent is CVE-2026-42248?

Priority 58/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Windows vulnerabilities

Related CVEs

CVE-2026-5757 HIGH 7.5 UPGRADE Unauthenticated remote information disclosure vulnerability in Ollama's model quantization engine allows an at
CVE-2026-15685 HIGH 7.5 DOWNGRADE Ollama downloadBlob Improper Validation of Array Index Denial-of-Service Vulnerability
CVE-2026-7482 CRITICAL 9.1 UPGRADE Ollama before 0.17.1 contains a heap out-of-bounds read vulnerability in the GGUF model loader
CVE-2026-7020 LOW 3.7 UPGRADE A security flaw has been discovered in Ollama up to 0.20.2
CVE-2026-42249 CRITICAL 9.8 UPGRADE Ollama for Windows contains a Remote Code Execution vulnerability in its update mechanism due to improper hand

References

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