Claude Code is an agentic coding tool. Prior to 2.1.251, the Edit tool validates a target using pathname and symlink resolution that is not bound to the underlying directory inode or file descriptor. On macOS, attacker-controlled code running in the Bash sandbox can atomically replace an in-workspace parent directory with a symlink after validation, causing the unsandboxed Edit implementation to overwrite a user-writable file outside the workspace. Exploitation requires attacker-controlled code to run inside the sandbox, such as from a malicious repository or dependency script. This issue is fixed in version 2.1.251.
https://github.com/anthropics/claude-code/security/advisories/GHSA-5xjx-9qx6-jcrv
https://github.com/anthropics/claude-code/releases/tag/v2.1.251
Published: 2026-11-03
Updated: 2026-11-03
Base Score: 5.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:P
Severity: Medium
Base Score: 8.6
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Severity: High
Base Score: 7.7
Vector: 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
Severity: High
EPSS: 0.00317