CVE-2026-5366 — CRITICAL (9.9)

Vulnerability Description

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.

CVSS Score

9.9

CRITICAL

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Affected Products

Vendor	Product	Versions
Prefect	Prefect	3.6.23

Related Weaknesses (CWE)

CWE-94

References

https://huntr.com/bounties/e2e88a0f-a8f6-49c9-94c5-e98dc385f07aExploitThird Party Advisory
https://huntr.com/bounties/e2e88a0f-a8f6-49c9-94c5-e98dc385f07aExploitThird Party Advisory

FAQ

What is CVE-2026-5366?

CVE-2026-5366 is a vulnerability with a CVSS score of 9.9 (CRITICAL). 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...

How severe is CVE-2026-5366?

CVE-2026-5366 has been rated CRITICAL with a CVSS base score of 9.9/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-5366?

Check the references section above for vendor advisories and patch information. Affected products include: Prefect Prefect.