CVE-2026-121751

What it is

Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.39.6 through 0.40.8, `nvm ls-remote` (and other commands that refresh remote LTS aliases) store the version column of the mirror's `index.tab` in `$NVM_DIR/alias/lts/` without validating it, and `nvm_normalize_lts` later evaluates any suffix of an `lts/-N` value inside shell arithmetic `$((N+1))`. Under bash and zsh, arithmetic evaluation expands command substitutions in array subscripts, so a stored value such as `lts/-10*path[$(cmd)1]` runs `cmd` as the user when the alias is later resolved by purely local commands (`nvm ls`, `nvm alias`, `nvm use --lts`, `nvm which lts/`), and in every new shell when the `default` alias is `lts/*`. Exploitation requires the victim to use a hostile mirror -- via a compromised mirror or CDN, a network man-in-the-middle of an `http://` mirror, or a maliciously configured `NVM_NODEJS_ORG_MIRROR` -- and to run an affected command. The same sink is also reachable from a project `.nvmrc`, which is treated as hardening. dash is not affected. Version 0.41.0 only passes an all-digit `lts/-N` offset to arithmetic and drops `index.tab` rows whose version is not a valid version string.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-11-04 22:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-10 21:46 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 2.1 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-11-04 22:17 UTC

Last modified

2026-11-10 21:46 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 2.1

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

Active

Confidentiality

None

Integrity

Low

Availability

None

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-2026-121751.md and follow it. Check whether this project is affected by CVE-2026-121751. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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