Data exfiltration via prefix-based domain validation bypass
Published Feb 3, 2026 · Updated Feb 3, 2026
Domain-validation bypass in Anthropic Claude Code before 1.0.111 allows remote attackers to trigger WebFetch requests to untrusted hosts. The trusted-domain check applies startsWith() to a hostname string, so an attacker-owned hostname beginning with an allowlisted domain is treated as trusted. The affected flow requires passive user interaction; successful exploitation sends WebFetch request data to the attacker-controlled host without a consent prompt.
Summary
What happened
Domain-validation bypass in Anthropic Claude Code before 1.0.111 allows remote attackers to trigger WebFetch requests to untrusted hosts. The trusted-domain check applies startsWith() to a hostname string, so an attacker-owned hostname beginning with an allowlisted domain is treated as trusted. The affected flow requires passive user interaction; successful exploitation sends WebFetch request data to the attacker-controlled host without a consent prompt.
The record
- CVE
- CVE-2026-24052
- Published
- Feb 3, 2026
- Updated
- Feb 3, 2026
- Vendor
- Anthropic
- Product
- Claude Code
- Classifications
- CWE-601, T1048
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 3, 2026CVE publishedPublication date reported by the CVE source.
- Feb 3, 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.
- Affected versionversion=< 1.0.111
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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