CVE-2026-54316Network attack vector

Data exfiltration via pre-approved WebFetch hostname

Published Jun 23, 2026 · Updated Jun 23, 2026

Information disclosure in Anthropic Claude Code 0.2.54 through 2.1.162 allows attackers to exfiltrate data via WebFetch. A bare-hostname allowlist entry for huggingface.co auto-approves every path, letting injected instructions encode accessible data in requests to attacker-controlled repository files whose server-side download records reveal the values. Exploitation requires untrusted content in the context window and exposes files, environment variables, or command output available to the running agent.

CVSS severity6.0
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Anthropic Claude Code 0.2.54 through 2.1.162 allows attackers to exfiltrate data via WebFetch. A bare-hostname allowlist entry for huggingface.co auto-approves every path, letting injected instructions encode accessible data in requests to attacker-controlled repository files whose server-side download records reveal the values. Exploitation requires untrusted content in the context window and exposes files, environment variables, or command output available to the running agent.

The record

CVE
CVE-2026-54316
Published
Jun 23, 2026
Updated
Jun 23, 2026
Vendor
Anthropic
Product
Claude Code
Classifications
CWE-515, CWE-200, CWE-183, T1567
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 23, 2026Record 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=>= 0.2.54, < 2.1.163

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Anthropic · Claude Codeversion=>= 0.2.54, < 2.1.163

Published CVSS scores

6.0GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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-515Covert Storage Channel
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
CWE-183Permissive List of Allowed Inputs
T1567Exfiltration Over Web Service

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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