Is CVE-2026-100841 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100841 being exploited in the wild.

How severe is CVE-2026-100841?

High severity, with a CVSS score of 7.8, published 27 September 2026.

Which products and versions are affected?

Project-MONAI MONAI all released versions (0 and higher); monai (PyPI) ECOSYSTEM:introduced=0,last_affected=1.6.0-NA.

Is there a fix for CVE-2026-100841?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-100841 attacked?

It is attacked with local access, in a software library.

Am I affected by CVE-2026-100841?

Check whether you run Project-MONAI MONAI or monai (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100841: Project-MONAI MONAI pickle deserialization in cache

CVE-2026-100841 · Severity: high · CVSS 7.8 · Published 2026-09-27

MONAI is a medical imaging AI framework that caches processed data locally to improve performance. A flaw in how MONAI handles cached data allows any local user who can write to the cache directory (common on shared systems like HPC clusters) to insert malicious files that execute arbitrary code when another user's MONAI pipeline reads the cache. This affects all released versions with no patch available.

Technologies: Project-MONAI MONAI, monai (PyPI). Vendors: Project-MONAI, PyPI.

Quick answers

Is CVE-2026-100841 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100841 being exploited in the wild.
How severe is CVE-2026-100841?: High severity, with a CVSS score of 7.8, published 27 September 2026.
Which products and versions are affected?: Project-MONAI MONAI all released versions (0 and higher); monai (PyPI) ECOSYSTEM:introduced=0,last_affected=1.6.0-NA.
Is there a fix for CVE-2026-100841?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-100841 attacked?: It is attacked with local access, in a software library.
Am I affected by CVE-2026-100841?: Check whether you run Project-MONAI MONAI or monai (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability stems from PersistentDataset forcing weights_only=False in torch.load() when caching MetaTensors, combined with monai/data/utils.py using pickle.loads() to deserialize cached content and MD5 hashing for cache keys. An attacker with local write access to a shared cache directory can place a malicious pickle file that gets deserialized without validation, achieving arbitrary code execution in the victim's process context. No patched version exists as of the advisory date.

Affected products

Project-MONAI MONAI all released versions (0 and higher)

Identifiers

CVE-2026-100841
GHSA-636w-j999-g7x5
PYSEC-2026-4016

Timeline

2026-08-21: disclosed: GitHub security advisory GHSA-636w-j999-g7x5 published
2026-09-27: advisory: CVE-2026-100841 assigned

References

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