CVE-2026-5366
CriticalCVSS 9.9Exploitation Probability (EPSS)
Elevated risk55th percentile - higher than 55% of all known CVEs
Summary
Prefect version 3.6.23 is vulnerable to remote code execution due to improper handling of user-controlled input in the `GitRepository` storage class. The `commit_sha` parameter lacks validation and does not include a `--` separator, allowing injection of arbitrary git flags like `--upload-pack` to execute external programs. The `directories` parameter can also be exploited to inject git flags during sparse-checkout operations.
Risk Assessment
The risk for the organization is that any user with deployment creation permissions can execute arbitrary commands on worker machines, potentially compromising shared work pools in multi-tenant environments and leading to privilege escalation.
Recommendation
Immediately upgrade Prefect to version 3.6.24 or later, which includes fixes for this vulnerability. Until the update is applied, restrict deployment creation permissions to trusted users only.
Other vulnerabilities in Prefect
See all- CVE-2026-72538High
An argument injection vulnerability in PrefectHQ Prefect through 3.8.2 allows authenticated users to achieve remote code execution via the git_clone pull step branch field. The branch parameter is passed directly to git pull without sanitization, enabling injection of arbitrary git arguments. This represents a distinct code path from the incomplete fix applied for CVE-2026-5366 and allows command execution on the Prefect server.
- CVE-2026-3515High
In Prefect version 3.6.18, the prefect-github integration injects the reference field into a git clone command without sanitization, allowing injection of git options. This can lead to SSRF, credential theft, or RCE.
Original NVD description (English source)
Prefect version 3.6.23 is vulnerable to remote code execution due to improper handling of user-controlled input in the `GitRepository` storage class. The `commit_sha` parameter, which is passed to git commands, lacks validation and does not include a `--` separator to distinguish user input from git flags. This allows attackers to inject arbitrary git flags, such as `--upload-pack`, enabling execution of external programs. Additionally, the `directories` parameter can be exploited to inject git flags during sparse-checkout operations. These vulnerabilities allow any user with deployment creation permissions to execute arbitrary commands on worker machines, compromising shared work pools in multi-tenant environments.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS