CVE-2026-63478
What it is
isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git's tree parser in src/models/GitTree.js accepts a standalone .. tree-entry name because it rejects only path separators. During clone or checkout from a malicious or man-in-the-middle-controlled non-GitHub remote, nested .. entries can escape the working-tree root and write files at attacker-selected parent paths on any host-backed fs provider. The arbitrary file write can overwrite startup or configuration files and lead to code execution. GitHub-hosted trees are not a direct source because GitHub rejects .. entries during repository integrity checks. This issue is fixed in version 1.38.6.
At a glance
- Exploitability
- Can be exploited over the network without logging in, but needs a user to act. High risk of data tampering.
- Exploit odds
- 0.3% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.3% in the next 30 days (EPSS).
- Severity: 5.3 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.3% · EPSS, next 30 days
- Weakness
- CWE-22 · Path traversal
- Record status
- Deferred
Attack profile CVSS 3.1 · 5.3
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-63478.md and follow it. Check whether this project is affected by CVE-2026-63478. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b
- https://github.com/isomorphic-git/isomorphic-git/pull/2370
- https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6
- https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-cw2g-2vwq-88w6
- https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-cw2g-2vwq-88w6
References
- https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b
- https://github.com/isomorphic-git/isomorphic-git/pull/2370
- https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6
- https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-cw2g-2vwq-88w6
- https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-cw2g-2vwq-88w6