CVE-2026-55607
CVE-2026-55607 is a high-severity vulnerability in Anthropic Claude Code with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- CVSS v4: 7.7
- EPSS exploit prediction: 1% (51st percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-22
- Affected product: Anthropic Claude Code
- Published:
- Last modified:
Description
Claude Code is an agentic coding tool. From 2.1.38 until 2.1.163, Claude Code's worktree handling allowed creation of worktrees named ".git" and navigation to worktrees outside the sandbox context, enabling git directory confusion attacks. By exploiting symlink manipulation and git fsmonitor execution during worktree operations, an attacker could overwrite files in the user's home directory (such as .zshenv), leading to code execution outside of seatbelt sandbox restrictions. Reliably exploiting this required the user to clone a malicious repository containing prompt injection content and run Claude Code against it. This vulnerability is fixed in 2.1.163.
Frequently asked questions
- What is CVE-2026-55607?
- Claude Code is an agentic coding tool. From 2.1.38 until 2.1.163, Claude Code's worktree handling allowed creation of worktrees named ".git" and navigation to worktrees outside the sandbox context, enabling git directory confusion attacks. By exploiting symlink manipulation and git fsmonitor execution during worktree operations, an attacker could overwrite files in the user's home directory (such as .zshenv), leading to code execution outside of seatbelt sandbox restrictions. Reliably exploiting this required the user to clone a malicious repository containing prompt injection content and run Claude Code against it. This vulnerability is fixed in 2.1.163.
- How severe is CVE-2026-55607?
- CVE-2026-55607 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-55607 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-55607?
- CVE-2026-55607 affects Anthropic Claude Code. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-55607?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-55607 published?
- CVE-2026-55607 was published on 2026-06-29 and last updated on 2026-06-30.
References
Affected products (1)
- cpe:2.3:a:anthropic:claude_code:*:*:*:*:*:node.js:*:*
More vulnerabilities in Anthropic Claude Code
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- CVE-2025-66032 — Critical (CVSS 9.8): Claude Code is an agentic coding tool. Prior to 1.0.93, Due to errors in parsing shell commands related to $IFS and…
- CVE-2025-64755 — Critical (CVSS 9.8): Claude Code is an agentic coding tool. Prior to version 2.0.31, due to an error in sed command parsing, it was possible…
- CVE-2025-65099 — Critical (CVSS 9.8): Claude Code is an agentic coding tool. Prior to version 1.0.39, when running on a machine with Yarn 3.0 or above,…
- CVE-2025-59828 — Critical (CVSS 9.8): Claude Code is an agentic coding tool. Prior to Claude Code version 1.0.39, when using Claude Code with Yarn versions…
All CVEs affecting Anthropic Claude Code →
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