Description
Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.31.2 through 0.40.5, `nvm_ls` filters installed versions with a sed program that embeds the requested version pattern in a `\#...#` address, escaping `.` (and, since 0.40.4, `#`) but not backslash. A version string containing `#` (or `\#`) therefore closes the address early, and the rest of it is parsed as sed commands: with GNU sed, the `e` command runs a shell command as the user; with BSD sed, the `w` and `r` commands write and read files. This is reachable whenever an attacker-influenced version string is passed to `nvm use`, `nvm which`, `nvm ls`, `nvm version`, `nvm run`, or `nvm exec`, or to `nvm-exec` via `NODE_VERSION`, and at least one version is installed. nvm's own `.nvmrc` parser strips comments, so a bare `nvm use` is not affected; however, the bash `cdnvm` and zsh `load-nvmrc` auto-switch hooks documented in the README read `.nvmrc` as-is and pass it to `nvm ls` and `nvm version`, so a user with one of those hooks installed runs the attacker's command just by changing into a directory under a malicious `.nvmrc`; scripts that run `nvm use "$(cat .nvmrc)"` are affected the same way. Version 0.40.6 passes any version pattern containing `#` or a newline through the `.nvmrc` content parser first, so no `#` reaches the sed program.
Published: 2026-10-29
Score: 7.1 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Solution

Upgrade to nvm 0.40.6 or later.

Vendor Workaround

Until upgrading, do not pass untrusted version strings to nvm, and use nvm's own `.nvmrc` handling (a bare `nvm use`) instead of reading `.nvmrc` yourself, including in shell auto-switch hooks.

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History

Thu, 29 Oct 2026 05:30:00 +0000

Type Values Removed Values Added
Description Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.31.2 through 0.40.5, `nvm_ls` filters installed versions with a sed program that embeds the requested version pattern in a `\#...#` address, escaping `.` (and, since 0.40.4, `#`) but not backslash. A version string containing `#` (or `\#`) therefore closes the address early, and the rest of it is parsed as sed commands: with GNU sed, the `e` command runs a shell command as the user; with BSD sed, the `w` and `r` commands write and read files. This is reachable whenever an attacker-influenced version string is passed to `nvm use`, `nvm which`, `nvm ls`, `nvm version`, `nvm run`, or `nvm exec`, or to `nvm-exec` via `NODE_VERSION`, and at least one version is installed. nvm's own `.nvmrc` parser strips comments, so a bare `nvm use` is not affected; however, the bash `cdnvm` and zsh `load-nvmrc` auto-switch hooks documented in the README read `.nvmrc` as-is and pass it to `nvm ls` and `nvm version`, so a user with one of those hooks installed runs the attacker's command just by changing into a directory under a malicious `.nvmrc`; scripts that run `nvm use "$(cat .nvmrc)"` are affected the same way. Version 0.40.6 passes any version pattern containing `#` or a newline through the `.nvmrc` content parser first, so no `#` reaches the sed program.
Title nvm_ls lets an untrusted version string inject sed commands, executing arbitrary commands with GNU sed
Weaknesses CWE-78
CWE-94
References
Metrics cvssV3_1

{'score': 7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 7.1, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

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cve-icon MITRE

Status: PUBLISHED

Assigner: harborist

Published:

Updated: 2026-10-29T05:22:35.156Z

Reserved: 2026-10-29T05:21:07.784Z

Link: CVE-2026-118905

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses