CVE-2026-59831 (CVSS 4.4)

Description

GitHub CLI (gh) is GitHub’s official command line tool. From 2.10.0 through 2.95.0, connecting to a malicious Codespace with gh codespace jupyter can allow command execution because the command opens a JupyterLab URL supplied by a process inside the Codespace without validating that it is a loopback HTTP or HTTPS address, allowing a crafted vscode:// or vscode-insiders:// URL to be handed to VS Code. This issue is fixed in version 2.96.0.

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CVSS v3.1 Score

4.4

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0020

Probability of exploitation

0.10%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-829 CWE-829

References

Other References

https://github.com/cli/cli/commit/b300f2ec7ec9dc9addc39b2ad88c54097ded7ca0 https://github.com/cli/cli/releases/tag/v2.96.0 https://github.com/cli/cli/security/advisories/GHSA-8cg3-r6g9-fpg2

Frequently Asked Questions

What is CVE-2026-59831? +

GitHub CLI (gh) is GitHub’s official command line tool. From 2.10.0 through 2.95.0, connecting to a malicious Codespace with gh codespace jupyter can allow command execution because the command opens a JupyterLab URL supplied by a process inside the Codespace without validating that it is a loopback HTTP or HTTPS address, allowing a crafted vscode:// or vscode-insiders:// URL to be handed to VS Code. This issue is fixed in version 2.96.0. It has a CVSS v3.1 base score of 4.4 (MEDIUM).

How severe is CVE-2026-59831? +

CVE-2026-59831 has a CVSS v3.1 score of 4.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0020, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-59831? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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