{"id":"CVE-2026-46406","aliases":["EUVD-2026-40116","GHSA-4vp2-6q8c-pvq2"],"status":"published","title":"Claude Code: Insecure Temporary File in /copy Command Enables Response Disclosure and Symlink-Based File Write","description":"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":{"version":"4.0","score":4.4,"vector":"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00154,"percentile":0.04528,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-200","CWE-377","CWE-59"],"published":"2026-06-25T16:53:00Z","modified":"2026-10-28T02:31:00Z","fixes":[{"ecosystem":"npm","package":"@anthropic-ai/claude-code","fixed_in":["2.1.128"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@anthropic-ai/claude-code","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.1.59"},{"fixed":"2.1.128"}]}]},{"source":"osv","ecosystem":"npm","package":"@anthropic-ai/claude-code","ranges":[{"type":"SEMVER","events":[{"introduced":"2.1.59"},{"fixed":"2.1.128"}]}]}],"products":[{"vendor":"anthropic","product":"claude_code"},{"vendor":"anthropics","product":"claude-code"}],"references":[{"url":"https://github.com/anthropics/claude-code/security/advisories/GHSA-4vp2-6q8c-pvq2","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://github.com/advisories/GHSA-4vp2-6q8c-pvq2"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46406.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46406","tags":["advisory"]},{"url":"https://github.com/anthropics/claude-code","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-46406","title":"Claude Code: Insecure Temporary File in /copy Command Enables Response Disclosure and Symlink-Based File Write","description":"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.","status":"published","published":"2026-06-29T14:03:14.683Z","modified":"2026-06-29T15:26:11.153Z","cvss":[{"version":"4.0","score":4.4,"vector":"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","level":"medium","assessor":"cna"}],"cwes":["CWE-59","CWE-200","CWE-377"],"updated_at":"2026-11-02T13:47:06.353366Z"}],"euvd":[{"id":"EUVD-2026-40116","description":"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.","status":"published","published":"2026-06-29T14:03:14Z","modified":"2026-06-29T15:26:11Z","cvss":[{"version":"4.0","score":4.4,"vector":"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","level":"medium"}],"updated_at":"2026-11-02T18:20:22.506413Z"}],"ghsa":[{"id":"GHSA-4vp2-6q8c-pvq2","title":"@anthropic-ai/claude-code has an Insecure Temporary File in /copy Command that Enables Response Disclosure and Symlink-Based File Write","description":"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.\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.","status":"published","published":"2026-06-25T16:53:00Z","modified":"2026-06-25T16:53:03Z","cvss":[{"version":"4.0","score":4.4,"vector":"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","level":"medium"}],"cwes":["CWE-59","CWE-200","CWE-377"],"updated_at":"2026-11-02T14:40:33.778544Z"}],"nvd":[{"id":"CVE-2026-46406","description":"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.","status":"published","published":"2026-06-29T15:16:41.033Z","modified":"2026-10-25T21:10:00.77Z","cvss":[{"version":"4.0","score":4.4,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:H","level":"medium","assessor":"primary"}],"cwes":["CWE-59","CWE-200","CWE-377"],"updated_at":"2026-11-02T14:12:26.508751Z"}],"osv":[{"id":"CVE-2026-46406","title":"Claude Code: Insecure Temporary File in /copy Command Enables Response Disclosure and Symlink-Based File Write","description":"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.","status":"published","published":"2026-06-29T14:03:14.683Z","modified":"2026-10-28T02:31:00.570835872Z","cvss":[{"version":"4.0","score":4.4,"vector":"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","level":"medium"}],"cwes":["CWE-200","CWE-377","CWE-59"],"updated_at":"2026-11-02T15:45:05.870292Z"},{"id":"GHSA-4vp2-6q8c-pvq2","title":"@anthropic-ai/claude-code has an Insecure Temporary File in /copy Command that Enables Response Disclosure and Symlink-Based File Write","description":"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.\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.","status":"published","published":"2026-06-25T16:53:00Z","modified":"2026-07-09T05:15:08.591063132Z","cvss":[{"version":"4.0","score":4.4,"vector":"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","level":"medium"}],"cwes":["CWE-200","CWE-377","CWE-59"],"updated_at":"2026-11-02T15:46:37.528068Z"}]}}