GCD AI RADAR
incidents/AIR-2026-0436

CVE-2026-21852: Claude Code Data Leak via Malicious Config

Attack on AI2 Disclosed vulnerabilityInfrastructure vulnerabilityData leak

A vulnerability in Claude Code allowed malicious repositories to exfiltrate data and API keys before trust confirmation. A patch has been issued via auto-updates.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

Details

type
Attack on AI
An AI model, agent or AI-powered product was the thing exploited, abused or leaked.
categories
  • Infrastructure vulnerabilityprimary
    CVEs and advisories in AI frameworks, inference servers, MCP servers, AI developer tools and hosting stacks.
  • Data leak
    Training data, chat logs, system prompts, model weights or other AI-system data exposed.
owasp llm top 10
mitre atlas
no technique for these categories
Both rows are derived from the type and categories (OWASP 2025 edition, ATLAS release 2026.09), not classified per record. How
severity
2 · Disclosed vulnerability
CVE or vendor advisory, patched or patchable, no confirmed exploitation.
targets
Anthropic, Framework / tooling
products
Claude Code
incident date
21 Jan 2026
first reported
21 Jan 2026
origin
GitHub Advisory Database
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
classifier confidence
0.95 · published at or above 0.80; see the methodology
tags
CVE-2026-21852 · data-leak · infra_vuln
record
created 2026-10-18 07:00Z · updated 2026-10-18 10:04Z · json

Sources · 2

  1. 2026-01-21
    CVE-2026-21852: Claude Code Leaks Data via Malicious Environment Configuration Before Trust Confirmation
    GitHub Advisory Database · github.com/advisories/GHSA-jh7p-qr78-84p7
  2. 2026-01-21
    CVE-2026-21852: Claude Code is an agentic coding tool.
    NVD · nvd.nist.gov/vuln/detail/CVE-2026-21852

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