{"id":"CVE-2026-63395","published":"2026-11-03T20:18:14.917","lastModified":"2026-11-03T22:19:47.677","description":"isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git's git.checkout writes new child paths through symlinked leading directory components without checking them. A malicious repository can first place a directory symlink and later replace the tree state with a child file beneath that path; the usual trigger is a clone followed by a later pull, while a single clone can trigger the issue when a symlink already exists or the consuming application accesses the tree. With Node fs on Linux or macOS, the operating system can resolve the write outside the working tree, permitting arbitrary host file writes and possible code execution. Node fs on Windows usually blocks the symlink plant without additional privilege, and browser or in-memory providers limit impact to their virtual filesystem and are affected only when they implement symlink creation and following. This issue is fixed in version 1.38.6.","cvssScore":8.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cwes":["CWE-22","CWE-59"],"vendors":[],"products":[],"references":[{"url":"https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b","tags":[]},{"url":"https://github.com/isomorphic-git/isomorphic-git/pull/2370","tags":[]},{"url":"https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6","tags":[]},{"url":"https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9qw7-j9xw-fv9c","tags":[]},{"url":"https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9qw7-j9xw-fv9c","tags":[]}],"exploitRefs":[{"url":"https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b","tags":[]},{"url":"https://github.com/isomorphic-git/isomorphic-git/pull/2370","tags":[]},{"url":"https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6","tags":[]},{"url":"https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9qw7-j9xw-fv9c","tags":[]},{"url":"https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9qw7-j9xw-fv9c","tags":[]}],"hasPoc":true,"ai":{"summary":"isomorphic-git prior to 1.38.6 fails to validate symlinked directory components during git.checkout, allowing a malicious repository to write files outside the working tree by first planting a symlink and later updating the tree to target a path beneath it; this can lead to arbitrary file writes on Linux/macOS systems using Node.js fs.","exploitability":"Exploitation requires the attacker to control the Git repository content and trigger checkout (e.g., via clone followed by pull), with UI interaction needed for initial user action, and Node.js on Linux/macOS being required for full impact.","blast_radius":"On affected systems, successful exploitation could enable remote code execution via overwriting critical files such as shell profiles or binary executables, or data exfiltration through arbitrary file writes to the host filesystem.","remediation":"Upgrade to isomorphic-git version 1.38.6 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["symlink-traversal","arbitrary-file-write","rce","git","nodejs"],"model":"garnet-coder","analyzedAt":"2026-11-04T09:58:01.260Z"}}