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CVE-2026-21852

Claude Code Leaks Data via Malicious Environment Configuration Before Trust Confirmation

Published: Jan 21, 2026Updated: Feb 2, 2026 Sources: CVE List NVD GHSA
NVD MITRE
7.5CVSS
HIGH

Claude Code is an agentic coding tool. Prior to version 2.0.65, vulnerability in Claude Code's project-load flow allowed malicious repositories to exfiltrate data including Anthropic API keys before users confirmed trust. An attacker-controlled repository could include a settings file that sets ANTHROPIC_BASE_URL to an attacker-controlled endpoint and when the repository was opened, Claude Code would read the configuration and immediately issue API requests before showing the trust prompt, potentially leaking the user's API keys. Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to version 2.0.65, which contains a patch, or to the latest version.

EPSS Score
0.0%
Top 89.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None

Weaknesses

CWE-522

Affected Products

claude code
anthropic
claude-code
anthropics
@anthropic-ai/claude-code
npm

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Credential Access
View detailed technique mapping

References

https://github.com/anthropics/claude-code/security/advisories/GHSA-jh7p-qr78-84p7
github.com
https://nvd.nist.gov/vuln/detail/CVE-2026-21852
nvd.nist.gov
https://github.com/anthropics/claude-code
github.com

Timeline

Published
Jan 21, 2026
Last Updated
Feb 2, 2026
News mentions
1

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