External risk intelligence

GitHub CLI Authorization Header Exposure

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-48501

This vulnerability exists within a command-line interface tool used by developers on local machines. It relates to client-side authentication behavior during specific CLI commands (such as verifying attestations or releases) and does not involve an internet-facing service, appliance, or server component that would be exposed to or reachable from the public internet.

Github Cli

before 2.93.0

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

The GitHub CLI, a tool for interacting with GitHub, has a vulnerability that could expose user authentication tokens to unintended external services. This occurs when the CLI makes requests to specific repositories, potentially sending sensitive credentials to sites that should not have them. The main concern is confirming if our environment uses this tool and is potentially exposed.

CLI token exposure to wrong hosts.
Affects GitHub API interactions.
Assess GitHub CLI usage and exposure.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by tricking a user into running specific GitHub CLI commands that interact with TUF repositories or release assets. The CLI's misconfigured HTTP client will inadvertently send the user's authentication token to unintended hosts, including those that are not part of the GitHub API. This exposure of the token could allow an attacker to impersonate the user or access sensitive information.

User runs vulnerable GitHub CLI commands.
Token sent to unintended external hosts.
Risk of authentication token compromise.

Live Threat

Current exploitation, exposure, and threat context

The GitHub CLI's authentication layer could mistakenly send user authentication tokens to unintended servers when verifying attestations or releases. This occurs because the tool incorrectly normalizes hostnames, potentially leading to tokens being sent to services that should not receive them, such as GitHub Pages sites or artifact storage.

User authentication tokens.
Requests to incorrect hosts.
Unauthorized access to account data.

Operational Fix

Recommended remediation, mitigation, and detection steps

The GitHub CLI tool's shared HTTP client can mistakenly send user authentication tokens to unintended hosts when verifying artifacts or attestations, potentially exposing sensitive information. Understanding where this tool is deployed and actively used is the critical first step, followed by confirming any exposure or business impact. This will allow for an informed remediation plan and assignment of ownership.

Ownership: Developer tool administrators or platform teams.
Verify first: Usage and artifact verification command execution.
Action: Plan targeted updates or mitigate command usage.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is the GitHub CLI and how is it used?

The GitHub CLI (gh) is the official command-line interface tool provided by GitHub. Developers use it to interact with GitHub services directly from their terminals, allowing them to manage repositories, pull requests, and automated workflows. It simplifies tasks like verifying release artifacts and software attestations, which involve fetching data from various external mirrors and storage locations.

What does CWE-863 mean for CVE-2026-48501?

CWE-863 refers to 'Incorrect Authorization.' In the context of this CVE, it means the GitHub CLI fails to properly verify or restrict which hosts receive a user's sensitive authentication token. Because the software uses a shared HTTP client with flawed host detection logic, it mistakenly sends these credentials to unauthorized servers during specific operations, violating the expected access control boundaries.

When does this vulnerability trigger?

The flaw triggers when you execute specific commands—such as gh attestation, gh release verify, or gh release verify-asset—that fetch data from external hosts. It does not trigger during standard git operations or unrelated commands. The issue occurs because the CLI's internal host normalization logic incorrectly treats certain subdomains or external endpoints as trusted GitHub API hosts.

Is my system at risk according to Halo Surface Signal?

Halo Surface Signal indicates that risk is very unlikely. Because this vulnerability resides in a local developer command-line tool rather than a public-facing server or network appliance, it cannot be reached or exploited over the internet by remote attackers. The threat requires a user to manually run the specific, vulnerable CLI commands on their own local machine.

How do I secure my environment against this issue?

The primary response is to update the GitHub CLI to version 2.93.0 or later, which resolves the incorrect token handling logic. Platform teams and developer tool administrators should audit usage to ensure developers are using the patched version. Since this is a client-side tool, focus on coordinating updates across developer workstations rather than managing network-level defenses.

References

github.com/cli/cli/security/advisories/GHSA-8xvp-7hj6-mcj9

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.