GHSA-ff64-7w26-62rf — high GitHub Advisory (CVE-2026-25725) in npm/@anthropic-ai/claude-code

Description

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.

Users on standard Claude Code auto-update received this fix automatically. Users performing manual updates are advised to update to the latest version.

Claude Code thanks hackerone.com/edbr for reporting this issue!

Basic information

Type: reviewed
Severity: high
Advisory on GitHub: Open advisory ↗
Repository advisory: Open repository advisory ↗
Source code: Browse source ↗
Published (advisory): 2026-02-06 19:14:33 UTC
Updated: 2026-02-06 19:14:34 UTC
GitHub reviewed: 2026-02-06 19:14:33 UTC
NVD published: 2026-02-06 18:16:00 UTC

Score	Percentile
0.02%	6.07%

CVSS Scores

Base score	Version	Severity	Vector
7.7	4.0	—	`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network. Attack complexity (AC:L) Exploitation conditions are straightforward and stable. Attack requirements (AT:P) Additional preconditions must be present for exploitation. Privileges required (PR:N) No privileges are required. User interaction (UI:P) A user has to participate (for example click/open/approve). Vulnerable system confidentiality impact (VC:H) High confidentiality impact on the vulnerable system. Vulnerable system integrity impact (VI:H) High integrity impact on the vulnerable system. Vulnerable system availability impact (VA:H) High availability impact on the vulnerable system. Subsequent system confidentiality impact (SC:N) No confidentiality impact on subsequent systems. Subsequent system integrity impact (SI:N) No integrity impact on subsequent systems. Subsequent system availability impact (SA:N) No availability impact on subsequent systems.

Identifiers

Type	Value
GHSA	GHSA-ff64-7w26-62rf ↗
CVE	CVE-2026-25725 ↗

CWEs

CWE id	Name
CWE-501	Trust Boundary Violation
CWE-668	Exposure of Resource to Wrong Sphere

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem	Package	Vulnerable range	First patched	Vulnerable functions
npm	@anthropic-ai/claude-code	< 2.1.2	2.1.2	—

Claude Code has Sandbox Escape via Persistent Configuration Injection in settings.json