CVE-2024-39897: Cache driver GetBlob() allows read access to any blob without access control check

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-09 · updated 2026-06-17
Weakness: CWE-639

Description

zot is an OCI image registry. Prior to 2.1.0, the cache driver `GetBlob()` allows read access to any blob without access control check. If a Zot `accessControl` policy allows users read access to some repositories but restricts read access to other repositories and `dedupe` is enabled (it is enabled by default), then an attacker who knows the name of an image and the digest of a blob (that they do not have read access to), they may maliciously read it via a second repository they do have read access to. This attack is possible because [`ImageStore.CheckBlob()` calls `checkCacheBlob()`](https://github.com/project-zot/zot/blob/v2.1.0-rc2/pkg/storage/imagestore/imagestore.go#L1158-L1159) to find the blob a global cache by searching for the digest. If it is found, it is copied to the user requested repository with `copyBlob()`. The attack may be mitigated by configuring "dedupe": false in the "storage" settings. The vulnerability is fixed in 2.1.0.

Affected products

project-zot zot: before 2.1.0 — fixed in 2.1.0

How to fix

Upgrade to a fixed version: project-zot zot 2.1.0. Check the vendor advisory for mitigations.

References

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