Paper/Archive/CVE-2026-25725

CVE-2026-25725

anthropics claude-code — Claude Code Has Sandbox Escape via Persistent Configuration Injection in settings.json

CVSS 10.0 (NVD)10.0 / 10 × 3030.0 Not in CISA KEV+300.0 EPSS percentile 45.3.453 × 209.1 No public exploit+100.0 SSVC exploitation: none+100.0

Description · from the CVE record

Claude Code is an agentic coding tool. Prior to version 2.1.2, Claude Code's bubblewrap sandboxing mechanism failed to properly protect the .claude/settings.json configuration file when it did not exist at startup. While the parent directory was mounted as writable and .claude/settings.local.json was explicitly protected with read-only constraints, settings.json was not protected if it was missing. This allowed malicious code running inside the sandbox to create this file and inject persistent hooks (such as SessionStart commands) that would execute with host privileges when Claude Code was restarted. This issue has been patched in version 2.1.2.

Affected

ProductAffectedFixed inSource

claude-code< 2.1.2–CNA

Scores by source

NVD10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

GitHub_M (CNA)7.7CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refgithub.com/anthropics/claude-code/security/advisories/GHSA-ff64-7w26-62rf