CVE-2026-15921: Path Traversal (CVSS 3.1)

Description

Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.32.1 through 0.40.5, `nvm ls-remote` (and other commands that refresh remote LTS aliases, such as `nvm install --lts`) parse the node.js mirror's `index.tab` and use each release's LTS codename field as an alias filename without validating it. A malicious, compromised, or man-in-the-middled mirror can return an LTS codename containing path-traversal sequences such as `../../../.bashrc`, causing nvm to write the associated version string to a path outside `$NVM_DIR/alias`. With the default layout (`$NVM_DIR` is `~/.nvm`), this can create or overwrite files in the user's home directory, including shell startup files, which can lead to code execution in a later shell session. Exploitation requires the victim to use a hostile mirror -- via a compromised mirror or CDN, a network man-in-the-middle, or a maliciously configured `NVM_NODEJS_ORG_MIRROR`/`NVM_IOJS_ORG_MIRROR` -- and to run an affected command. Version 0.40.6 validates remote LTS codenames as safe alias filenames and rejects `..` path components when writing alias files.

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CVSS v3.1 Score

3.1

LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS — Exploit Prediction

0.0023

Probability of exploitation

0.13%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-22 Path Traversal

CWE-73 CWE-73

References

Other References

https://github.com/nvm-sh/nvm/commit/9275c5badda1d9d0cdad6f34598a111033eadb42 https://github.com/nvm-sh/nvm/security/advisories/GHSA-4ghp-wxpw-rhpg https://github.com/nvm-sh/nvm/security/advisories/GHSA-4ghp-wxpw-rhpg

Frequently Asked Questions

What is CVE-2026-15921? +

Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.32.1 through 0.40.5, `nvm ls-remote` (and other commands that refresh remote LTS aliases, such as `nvm install --lts`) parse the node.js mirror's `index.tab` and use each release's LTS codename field as an alias filename without validating it. A malicious, compromised, or man-in-the-middled mirror can return an LTS codename containing path-traversal sequences such as `../../../.bashrc`, causing nvm to write the associated version string to a path outside `$NVM_DIR/alias`. With the default layout (`$NVM_DIR` is `~/.nvm`), this can create or overwrite files in the user's home directory, including shell startup files, which can lead to code execution in a later shell session. Exploitation requires the victim to use a hostile mirror -- via a compromised mirror or CDN, a network man-in-the-middle, or a maliciously configured `NVM_NODEJS_ORG_MIRROR`/`NVM_IOJS_ORG_MIRROR` -- and to run an affected command. Version 0.40.6 validates remote LTS codenames as safe alias filenames and rejects `..` path components when writing alias files. It has a CVSS v3.1 base score of 3.1 (LOW).

How severe is CVE-2026-15921? +

CVE-2026-15921 has a CVSS v3.1 score of 3.1 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0023, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-15921? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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