isomorphic-git up to 1.38.5 Symlink git.checkout link following

Summaryinfo

A vulnerability, which was classified as critical, was found in isomorphic-git up to 1.38.5. The impacted element is the function git.checkout of the component Symlink. Executing a manipulation can lead to link following. This vulnerability appears as CVE-2026-63395. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in isomorphic-git up to 1.38.5. It has been declared as critical. This vulnerability affects the function git.checkout of the component Symlink. The manipulation with an unknown input leads to a link following vulnerability. The CWE definition for the vulnerability is CWE-59. The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-63395 since 07/16/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

Upgrading to version 1.38.6 eliminates this vulnerability.

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Productinfo

Type

• Versioning Software

Name

• isomorphic-git

Version

• 1.38.0
• 1.38.1
• 1.38.2
• 1.38.3
• 1.38.4
• 1.38.5

Website

• Product: https://github.com/isomorphic-git/isomorphic-git/

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