CVE-2026-3515 — prefect
HIGHCVE-2026-3515 is a high-severity (CVSS 8.5) CWE-88 vulnerability in prefect. No vendor fix is recorded yet; mitigation options are listed below.
Prefect has an Argument Injection issue
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-3515.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-3515 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 384,534 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
prefectReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
A vulnerability in the GitHubRepository block of the prefect-github integration in Prefect version 3.6.18 allows an attacker to inject arbitrary git command-line options via the reference field. The reference field is concatenated directly into a git clone command string without proper sanitization, and then parsed by shlex.split(). This enables injection of options such as -c, leading to potential Server-Side Request Forgery (SSRF), credential theft, or remote code execution (RCE). The vulnerability affects both the aget_directory() and get_directory() methods in src/integrations/prefect-github/prefect_github/repository.py. This issue does not affect the GitLab and BitBucket integrations, which use a safer list-based command construction approach.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | prefect | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for prefect, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of prefect has shipped for CVE-2026-3515 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.
Frequently Asked Questions
Is CVE-2026-3515 in your dependencies?
Find it across PyPI, including transitive dependencies.