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PrefectApplication

CVE-2026-5366

CRITICAL · 9.9 CVSS v3.0 Published 2026-06-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Prefect 3.6.23 GitRepository storage class improperly handles user-controlled `commit_sha` and `directories` parameters when constructing git commands. Without input validation or a `--` separator, attackers can inject git flags like `--upload-pack` to achieve arbitrary command execution on worker machines.

MitigationImplement strict input validation for commit_sha (ensure valid SHA format) and add `--` separator before user input in all git command constructions. Apply the same fix to the directories parameter for sparse-checkout operations.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PrefectApplication
Affected:= 3.6.23

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Prefect version
    Run 'prefect --version' or 'pip show prefect' to determine the installed version of Prefect
    Affected if The version is 3.6.23
  2. Identify GitRepository usage
    Search deployment configuration files, flow code, or infrastructure-as-code definitions for imports or usage of 'GitRepository' from prefect or storage classes
    Affected if GitRepository storage class is configured in any deployment
  3. Inspect deployment storage configurations
    Review deployments via 'prefect deployment ls' and inspect storage blocks using 'prefect block ls' and 'prefect block get', looking for GitRepository-type blocks
    Affected if A GitRepository storage block exists with user-provided commit_sha or directories values
  4. Check for exposed deployment creation endpoints
    If Prefect Server or Cloud API is exposed, review access controls on deployment creation/modification endpoints
    Affected if Users with deployment creation permissions exist in a multi-tenant environment
  5. Audit deployment creation permissions
    Review IAM, API keys, or RBAC policies to identify which users or service accounts can create or modify deployments that reference GitRepository storage
    Affected if Non-admin users or service accounts have deployment creation/modification privileges

You are affected if running Prefect version 3.6.23 AND have deployments using GitRepository storage where commit_sha or directories parameters can be controlled by users with deployment creation permissions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict input validation for commit_sha (ensure valid SHA format) and add `--` separator before user input in all git command constructions. Apply the same fix to the directories parameter for sparse-checkout operations.

Recommended fix Moderate confidence

Prefect version > 3.6.23 (e.g., 3.6.24 or latest stable release)

  1. 1. Identify all Prefect deployments using GitRepository storage in version 3.6.23
  2. 2. Upgrade Prefect server and workers to a version newer than 3.6.23 (e.g., 3.6.24 or latest stable)
  3. 3. After upgrade, verify that the GitRepository storage class properly validates the commit_sha parameter and uses `--` separator in git commands
  4. 4. Test that the directories parameter is properly handled during sparse-checkout operations
  5. 5. Review deployment creation permissions to ensure only trusted users can create deployments with GitRepository storage
Caveat Review release notes for any breaking changes between 3.6.23 and the target version before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Prefect Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-5366 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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