Is CVE-2026-21852 actively exploited?

CVE-2026-21852 has no public evidence of in-the-wild exploitation as of 2026-02-02.

What is the CVSS score for CVE-2026-21852?

CVE-2026-21852 has a CVSS score of 5.3 (MEDIUM severity). Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

How do I patch CVE-2026-21852?

Patch guidance is available from anthropic security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-21852.

Which products are affected by CVE-2026-21852?

1 product: anthropic claude code.

CVE-2026-21852 - remediation guidance & executive summary

Description

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.

CVSS Metrics

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector: network
Complexity: low
Privileges: none
User Action: passive
Confidentiality: undefined
Integrity: undefined
Availability: undefined
Weaknesses: CWE-522 · Insufficiently Protected Credentials

Metadata

Primary Vendor: ANTHROPIC
Published: 1/21/2026
Last Modified: 2/2/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

anthropic : claude_code

Remediation Guidance

Executive Summary

Cite this page

CVE-2026-21852. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2026-21852

View on NIST NVD

CVE-2026-21852 vulnerability