CVE-2026-54316 Details
Description
Claude Code is an agentic coding tool. From 0.2.54 until 2.1.163, because the hostname huggingface.co was pre-approved as a bare hostname for the WebFetch tool, any path on that domain—including attacker-controlled model repositories—was auto-approved without a permission prompt or being subject to --allowedTools restrictions. An attacker able to inject untrusted content into a Claude Code context could direct it to issue WebFetch requests against attacker-controlled repository files (e.g. /resolve/main/config.json), which HuggingFace counts as downloads server-side, creating a covert out-of-band channel for encoding and exfiltrating data Claude can access such as files, environment variables, or command output. Reliably exploiting this required the ability to add untrusted content into a Claude Code context window. This vulnerability is fixed in 2.1.163.
A vulnerability in Claude Code versions 0.2.54 through 2.1.163 allows for unauthorized data exfiltration using the WebFetch tool. The issue arises because the hostname huggingface.co was pre-approved, enabling automatic approval of any path on that domain, including those in attacker-controlled model repositories. This lack of permission prompt or adherence to allowed tools restrictions created a covert channel for exfiltrating data accessible to Claude, such as files, environment variables, or command output. The vulnerability could be exploited by injecting untrusted content into a Claude Code context, directing it to make WebFetch requests for files from the compromised Hugging Face repositories. Hugging Face counts these file accesses as downloads, further masking the exfiltration activity.
Users on standard Claude Code auto-update have already received the fix. Those performing manual updates should update to the latest version.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 23, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/anthropics/claude-code/security/advisories/GHSA-fg94-h982-f3mm | [email protected] | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-183 | Permissive List of Allowed Inputs | [email protected] |
| CWE-200 | Exposure of Sensitive Information to an Unauthorized Actor | [email protected] |
| CWE-515 | Covert Storage Channel | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| anthropic claude code | >= 0.2.54, < 2.1.163 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 29, 2026 | Initial Analysis | [email protected] |
| Jun 23, 2026 | New CVE Received | [email protected] |
| Jun 23, 2026 | CVE Modified | CISA-ADP |