CVE-2026-100841 MONAI through 1.6.0 PersistentDataset Remote Code Execution via Pickle Cache
A local attacker with write access to the cache directory can execute arbitrary code via malicious pickle files in MONAI's PersistentDataset.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-100841?
CVE-2026-100841 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, with no action from the victim.
Official description
In MONAI 1.6.0, PersistentDataset (monai/data/dataset.py) explicitly rejects the combination track_meta=True with weights_only=True, forcing users who cache MetaTensors (the default tensor type in MONAI >= 1.0) to run torch.load(hashfile, weights_only=False). Related cache helpers in monai/data/utils.py also call pickle.loads on cached content and derive cache keys with hashlib.md5. As a result, a local user with write access to a shared or world-writable cache_dir (e.g. /tmp/monai_cache, HPC scratch, ~/.cache/monai) can place a malicious pickle file that is deserialized the next time another user's MONAI pipeline reads the cache, resulting in arbitrary code execution in that user's context. All released versions of the monai pip package are affected; no patched version is available as of the advisory.
Weakness: CWE-502
Which versions are affected by CVE-2026-100841?
1 open source package ship an affected version, including monai. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
monai PyPI | All versions to 1.6.0-NA | None |
Products include Project-Monai Monai.
How do I fix CVE-2026-100841?
No fix has been published for CVE-2026-100841 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-100841 being exploited?
There is no known exploitation of CVE-2026-100841 in the wild and no public exploit code.
Other vulnerabilities in Project-MONAI MONAI
- CVE-2026-100846 MONAI before 1.5.2 Remote Code Execution via Pickle Deserialization
- CVE-2026-100844 MONAI before 1.6.0 OS Command Injection via dataset_name_or_id
- CVE-2026-100840 MONAI through 1.6.0 Remote Code Execution via bundle configuration
- CVE-2026-100843 MONAI before 1.6.0 Remote Code Execution via algo_from_pickle
- CVE-2026-100845 MONAI before 1.6.0 Remote Code Execution via NumpyReader
Sources
Also known as GHSA-636w-j999-g7x5, GHSA-wfpp-6gx5-h8xr, PYSEC-2026-4016.