Vulnerability-Lookup

CVE-2026-46406 (GCVE-0-2026-46406)

Vulnerability from cvelistv5 – Published: 2026-06-29 14:03 – Updated: 2026-06-29 15:26

Title

Claude Code: Insecure Temporary File in /copy Command Enables Response Disclosure and Symlink-Based File Write

Summary

Claude Code is an agentic coding tool. From 2.1.59 until 2.1.128, the Claude Code /copy command wrote responses to a hardcoded, predictable path (/tmp/claude/response.md) without UID isolation, randomness, or symlink protection. The file was created world-readable (0644) in a world-traversable directory (0755), allowing any local user to read a privileged user's Claude response, which could contain secrets or credentials. Additionally, because the path was static and predictable, a local attacker could pre-create the directory and plant a symlink at the expected file path, causing the privileged process to follow the symlink and overwrite an attacker-chosen file with the response text. Exploiting this required a local unprivileged user on the same system and a privileged user to run the /copy command. This vulnerability is fixed in 2.1.128.

Severity

4.4 (Medium)


                        
                          CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-59 - Improper Link Resolution Before File Access ('Link Following')
CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
CWE-377 - Insecure Temporary File

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/anthropics/claude-code/securit…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
anthropics	claude-code	Affected: >= 2.1.59, < 2.1.128

Show details on NVD website

JSON

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GHSA-4VP2-6Q8C-PVQ2

Vulnerability from github – Published: 2026-06-25 16:53 – Updated: 2026-06-25 16:53

Summary

@anthropic-ai/claude-code has an Insecure Temporary File in /copy Command that Enables Response Disclosure and Symlink-Based File Write

Details

The Claude Code /copy command wrote responses to a hardcoded, predictable path (/tmp/claude/response.md) without UID isolation, randomness, or symlink protection. The file was created world-readable (0644) in a world-traversable directory (0755), allowing any local user to read a privileged user's Claude response, which could contain secrets or credentials. Additionally, because the path was static and predictable, a local attacker could pre-create the directory and plant a symlink at the expected file path, causing the privileged process to follow the symlink and overwrite an attacker-chosen file with the response text. Exploiting this required a local unprivileged user on the same system and a privileged user to run the /copy command.

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

Claude Code thanks hackerone.com/c_h4ck_0 for reporting this issue.

Severity

4.4 (Medium)


                  
                    CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@anthropic-ai/claude-code"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.1.59"
            },
            {
              "fixed": "2.1.128"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-46406"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-59",
      "CWE-200",
      "CWE-377"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-25T16:53:00Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "The Claude Code `/copy` command wrote responses to a hardcoded, predictable path (`/tmp/claude/response.md`) without UID isolation, randomness, or symlink protection. The file was created world-readable (0644) in a world-traversable directory (0755), allowing any local user to read a privileged user\u0027s Claude response, which could contain secrets or credentials. Additionally, because the path was static and predictable, a local attacker could pre-create the directory and plant a symlink at the expected file path, causing the privileged process to follow the symlink and overwrite an attacker-chosen file with the response text. Exploiting this required a local unprivileged user on the same system and a privileged user to run the `/copy` command.\n\nUsers on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version.\n\nClaude Code thanks hackerone.com/c_h4ck_0 for reporting this issue.",
  "id": "GHSA-4vp2-6q8c-pvq2",
  "modified": "2026-06-25T16:53:00Z",
  "published": "2026-06-25T16:53:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/anthropics/claude-code/security/advisories/GHSA-4vp2-6q8c-pvq2"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/anthropics/claude-code"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "@anthropic-ai/claude-code has an Insecure Temporary File in /copy Command that Enables Response Disclosure and Symlink-Based File Write"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-46406 (GCVE-0-2026-46406)

GHSA-4VP2-6Q8C-PVQ2

Tags

Sightings

Nomenclature