CVE-2026-121747

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CVE-2026-121747

Summary: nvm prints the contents of any readable file through a symlinked .nvmrc

Details: Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.2.0 through 0.40.8, nvm does not check whether `.nvmrc` is a symbolic link. A repository or archive that ships `.nvmrc` as a symlink to another file (for example `../../.npmrc`, or `/proc/self/environ` on Linux) makes a plain `nvm use`, `nvm install`, `nvm which`, `nvm exec`, `nvm run`, or `nvm-exec` read that file and print its contents in the invalid-`.nvmrc` message (even with `--silent`) or, for a one-line file, in the `Found ... with version <...>` message; with the README's zsh `load-nvmrc` or bash `cdnvm` hook installed, entering the directory is enough. nvm sends the content nowhere; the attacker learns it only where they can see the victim's output, such as a CI log for a contributed branch. Version 0.41.0 still follows a symlinked `.nvmrc`, so deliberate links to another version file keep working, but never prints its content, and accepts it only if it contains a version or the name of an existing alias; the README's bash `cdnvm` hook, which read `.nvmrc` itself, now gets the version from nvm, so users of that hook must also update their copy of it.

References: https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/121xxx/CVE-2026-121747.json, https://github.com/nvm-sh/nvm/security/advisories/GHSA-j6ch-mq5c-3h4x, https://nvd.nist.gov/vuln/detail/CVE-2026-121747, https://github.com/nvm-sh/nvm/commit/67268ebcb6e1a26ae3d71b3710d6333bb7358662, https://github.com/nvm-sh/nvm/commit/c314f1cbb3c301c587a4e4f96511d31f1134ffd1, https://github.com/nvm-sh/nvm