CVE-2021-39159Network attack vector

Remote code execution via unsafe git arguments

Published Aug 25, 2021 · Updated Aug 4, 2024

Remote code execution in JupyterHub BinderHub before 0.2.0-n653 allows remote attackers to execute commands through crafted repository input. GitRepoProvider passes an attacker-controlled repository or ref to git ls-remote without the option terminator, allowing argument injection that changes command behavior. The request reaches this path through BinderHub's repository provider; successful exploitation can expose deployment credentials and manipulate images or pods, with host escalation depending on Kubernetes configuration.

CVSS severity9.8
Critical
EPSS probability1.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in JupyterHub BinderHub before 0.2.0-n653 allows remote attackers to execute commands through crafted repository input. GitRepoProvider passes an attacker-controlled repository or ref to git ls-remote without the option terminator, allowing argument injection that changes command behavior. The request reaches this path through BinderHub's repository provider; successful exploitation can expose deployment credentials and manipulate images or pods, with host escalation depending on Kubernetes configuration.

The record

CVE
CVE-2021-39159
Published
Aug 25, 2021
Updated
Aug 4, 2024
Vendor
JupyterHub
Product
BinderHub
Classifications
CWE-94, CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.2.0-n653

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

JupyterHub · BinderHubversion=< 0.2.0-n653

Published CVSS scores

9.6GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Command and Scripting Interpreter: Unix Shell

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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