Critical

remote code execution via git repo provider

  • Disclosed: 25.08.2021
  • Updated: 11.10.2026 13:19

Impact

A remote code execution vulnerability has been identified in BinderHub, where providing BinderHub with maliciously crafted input could execute code in the BinderHub context, with the potential to egress credentials of the BinderHub deployment, including JupyterHub API tokens, kubernetes service accounts, and docker registry credentials. This may provide the ability to manipulate images and other user created pods in the deployment, with the potential to escalate to the host depending on the underlying kubernetes configuration.

Patches

Patch below, or on GitHub

diff
From 9f4043d9dddc1174920e687773f27b7933f48ab6 Mon Sep 17 00:00:00 2001
From: Riccardo Castellotti <rcastell@cern.ch>
Date: Thu, 19 Aug 2021 15:49:43 +0200
Subject: [PATCH] Explicitly separate git-ls-remote options from positional
 arguments

---
 binderhub/repoproviders.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/binderhub/repoproviders.py b/binderhub/repoproviders.py
index f33347b..5d4b87c 100755
--- a/binderhub/repoproviders.py
+++ b/binderhub/repoproviders.py
@@ -484,7 +484,7 @@ class GitRepoProvider(RepoProvider):
             self.sha1_validate(self.unresolved_ref)
         except ValueError:
             # The ref is a head/tag and we resolve it using `git ls-remote`
-            command = ["git", "ls-remote", self.repo, self.unresolved_ref]
+            command = ["git", "ls-remote", "--", self.repo, self.unresolved_ref]
             result = subprocess.run(command, universal_newlines=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
             if result.returncode:
                 raise RuntimeError("Unable to run git ls-remote to get the `resolved_ref`: {}".format(result.stderr))
-- 
2.25.1

Workarounds

Disable the git repo provider by specifying the BinderHub.repo_providers config, e.g.:

python
from binderhub.repoproviders import (GitHubRepoProvider,
                            GitLabRepoProvider, GistRepoProvider,
                            ZenodoProvider, FigshareProvider, HydroshareProvider,
                            DataverseProvider)

c.BinderHub.repo_providers =  {
            'gh': GitHubRepoProvider,
            'gist': GistRepoProvider,
            'gl': GitLabRepoProvider,
            'zenodo': ZenodoProvider,
            'figshare': FigshareProvider,
            'hydroshare': HydroshareProvider,
            'dataverse': DataverseProvider,
        }

References

Credit: Jose Carlos Luna Duran (CERN) and Riccardo Castellotti (CERN).

For more information

If you have any questions or comments about this advisory:

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) binderhub < 0.2.0 0.2.0

References

CVSS score 9.6/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Weakness (CWE)
CWE-78, CWE-94
Platform
Python (PyPI)
Package
binderhub
Disclosed
25.08.2021
Updated
11.10.2026 13:19

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2021-371 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-9jjr-qqfp-ppwx - CC BY 4.0

Vulnerability history: binderhub

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

This is the only known vulnerability of this package.

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