nvm-sh nvm up to 0.40.5 Sed Parser nvm_ls NODE_VERSION os command injection

Summaryinfo

A vulnerability classified as problematic was found in nvm-sh nvm up to 0.40.5. This vulnerability affects the function nvm_ls of the component Sed Parser. Such manipulation of the argument NODE_VERSION leads to os command injection. This vulnerability is listed as CVE-2026-118905. The attack must be carried out locally. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in nvm-sh nvm up to 0.40.5 and classified as problematic. Affected by this issue is the function nvm_ls of the component Sed Parser. The manipulation of the argument NODE_VERSION with an unknown input leads to a os command injection vulnerability. Using CWE to declare the problem leads to CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-118905 since 10/29/2026. The exploitation is known to be easy. The attack needs to be approached locally. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1202.

Upgrading to version 0.40.6 eliminates this vulnerability.

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Productinfo

Vendor

• nvm-sh

Name

• nvm

Version

• 0.40.0
• 0.40.1
• 0.40.2
• 0.40.3
• 0.40.4
• 0.40.5

Website

• Product: https://github.com/nvm-sh/nvm/

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