Answer in brief
CVE-2026-96620 records a Critical severity (CVSS 9.2) vulnerability in Claude Agent SDK: Argument Injection via resume Option Allows Arbitrary Command Execution. The current sources do not mark it as known exploited. The current feed maps anthropics/claude-agent-sdk-python (generic), claude-agent-sdk (pip). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps anthropics/claude-agent-sdk-python (generic), claude-agent-sdk (pip). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| anthropics/claude-agent-sdk-pythongeneric | <0.2.121 | 0.2.121 |
| claude-agent-sdkpip | <0.2.121 | 0.2.121 |
Published upstream
Oct 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 16, 2026
Claude Agent SDK is a Python SDK for Claude Code. Prior to 0.2.121, the resume option is passed to the Claude CLI as a separate token without validation, so a dash-leading value is parsed as an independent CLI flag. An attacker can inject the --mcp-config flag to define a stdio MCP server, causing arbitrary command execution at CLI startup outside the SDK permission controls. The issue is exploitable when an application passes untrusted input as the session ID to resume. This issue is fixed in version 0.2.121.
Quoted source text, attributed separately from HOL analysis.