# CVE-2026-118684: MONAI check_hash insufficient integrity verification

Source: https://junglewise.ai/threats/cve-2026-118684-monai-before-1-6-1-contains-an-insufficient-integrity  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-28. Updated: 2026-10-28  
License: CC BY 4.0 with a link back

CVE-2026-118684 · Severity: medium · CVSS 5.9 · Published 2026-10-28

MONAI is a medical imaging AI framework that downloads neural network bundles, datasets, and model archives during execution. A flaw in the integrity check function allows attackers who intercept downloads or compromise registries to inject malicious files that are silently accepted, potentially leading to arbitrary code execution on systems using the framework.

Technologies: [Project-MONAI MONAI](https://junglewise.ai/threats/technologies/project-monai-monai). Vendors: [Project-MONAI](https://junglewise.ai/threats/vendors/project-monai).

## Quick answers

**Is CVE-2026-118684 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-118684 being exploited in the wild.

**How severe is CVE-2026-118684?** Medium severity, with a CVSS score of 5.9, published 28 October 2026.

**Which products and versions are affected?** Project-MONAI MONAI before 1.6.1.

**Is there a fix for CVE-2026-118684?** Yes: fixed in 1.6.1. Until then: Require hash_val as a mandatory parameter when downloading bundles, datasets, or model archives; use SHA-256 instead of MD5 for all hash verification operations. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-118684 attacked?** It is attacked over the network or from the adjacent network, in a software library.

**Am I affected by CVE-2026-118684?** Check whether you run Project-MONAI MONAI 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.

## How to fix

- Fixed in 1.6.1

Require hash_val as a mandatory parameter when downloading bundles, datasets, or model archives; use SHA-256 instead of MD5 for all hash verification operations.

## Technical details

The check_hash() function in monai/apps/utils.py silently returns True when hash_val is None, bypassing integrity verification entirely. The function defaults to MD5 hashing, which is collision-attackable. Multiple download call sites pass hash_val=None, allowing MITM attackers or registry compromises to substitute bundles, datasets, or model archives without detection, with downstream code execution risk via eval operations (F001/F002 chains).

## Affected products

- Project MONAI MONAI before 1.6.1

## Timeline

- 2026-10-13: disclosed
- 2026-10-28: advisory

## References

- [https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-hhh4-h52m-fqh6](https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-hhh4-h52m-fqh6)
- [https://www.vulncheck.com/advisories/monai-before-1.6.1-missing-integrity-verification-via-check-hash-in-downloads](https://www.vulncheck.com/advisories/monai-before-1.6.1-missing-integrity-verification-via-check-hash-in-downloads)

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