CVE-2026-100843 MONAI before 1.6.0 Remote Code Execution via algo_from_pickle

High 8.5 Published 27 Sep 2026 Updated 30 Sep 2026

Attackers can execute arbitrary code by providing malicious pickle files to the algo_from_pickle function in MONAI.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2026-100843?

CVE-2026-100843 is a high-severity unsafe deserialization vulnerability in Project-MONAI MONAI, published on 27 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official description

MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle() function due to unsafe pickle.loads() deserialization in monai/auto3dseg/utils.py. Attackers can craft malicious pickle files that execute arbitrary system commands when deserialized by the vulnerable function.

Weakness: CWE-502

Which versions are affected by CVE-2026-100843?

3 open source packages ship an affected version, including monai. It affects 1 product.

Package	Affected	Fixed in
`monai` PyPI	All versions	`1.6.0`
`monai` PyPI	All versions	`1.6.0`
`monai` PyPI	All versions	`1.6.0`

Products include Project-Monai Monai.

How do I fix CVE-2026-100843?

Upgrade monai to 1.6.0 or later.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2026-100843 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100843 exists.

Sources

Also known as GHSA-m8hq-fmc4-c3v2, GHSA-qxq5-qhx6-94qw, PYSEC-2026-4018.