Vulnerability in Prefecthq Prefecthq/prefect

CVE-2026-3515

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (38.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 38.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-3515: held from 0.003 to 0.005.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-3515?
CVE-2026-3515 is a high-severity vulnerability in Prefecthq Prefecthq/prefect, classified under Argument Injection. CVSS score: 8.5/10. Published 2026-05-24.
How severe is CVE-2026-3515?
High severity. CVSS v3 base score is 8.5 out of 10.