CVE-2021-39160: nbgitpuller is a Jupyter server extension to sync a git repository one-way to a local path

This month

CRITICAL 9.6UPGRADE

CVE-2021-39160 is a critical-severity flaw (CVSS 9.6) affecting nbgitpuller. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

nbgitpuller is a Jupyter server extension to sync a git repository one-way to a local path. Due to unsanitized input, visiting maliciously crafted links could result in arbitrary code execution in the user environment. This has been resolved in version 0.10.2 and all users are advised to upgrade. No work around exist for users who can not upgrade.

Why this priority

Critical severity

A fixed release or distro patch exists.

Risk facts

CVSS score	9.6 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.7% (top 22%)
CISA exploited list	No
Weakness	CWE-94, CWE-78
Published	2021-08-25
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: jupyterhub

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-08-25 18:15 UTCPublished CVE record published
2026-06-17 04:03 UTCUpdated Record last modified

jupyterhub nbgitpuller UPGRADE

Affected: >= 0.9.0 and < 0.10.2

Fixed in: 0.10.2

Safe to downgrade to: a release before 0.9.0

1. Check installed version

apt-cache policy nbgitpuller || rpm -q nbgitpuller || nbgitpuller --version

2. UPGRADE to 0.10.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nbgitpuller

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nbgitpuller

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.9.0 (Debian / Ubuntu)

apt-cache madison nbgitpuller sudo apt install nbgitpuller=<VERSION_BEFORE_0.9.0> sudo apt-mark hold nbgitpuller

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list nbgitpuller sudo dnf downgrade nbgitpuller-<VERSION_BEFORE_0.9.0> sudo dnf versionlock add nbgitpuller

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-39160?

nbgitpuller: upgrade to 0.10.2. Exact commands for each OS are on this page.

Is CVE-2021-39160 being exploited?

CVE-2021-39160 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-39160 affect?

CVE-2021-39160 affects nbgitpuller. Severity is critical (CVSS 9.6). nbgitpuller is a Jupyter server extension to sync a git repository one-way to a local path. Due to unsanitized input, visiting maliciously crafted links could result in arbitrary code execution in the user environment. This has been resolve

How urgent is CVE-2021-39160?

Priority 53/100. Critical severity

Software pages

Git vulnerabilities · Jupyter vulnerabilities

References

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