{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-121751 in the wild and no public exploit code.","exposure":"","fix":"No fix has been published for CVE-2026-121751 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-121751 is a low-severity vulnerability in nvm-sh nvm, published on 4 Nov 2026."},"fix_prompt":"Check this codebase for CVE-2026-121751 and fix it if it is affected.\n\nWhat it is: CVE-2026-121751 is a low-severity vulnerability in nvm-sh nvm, published on 4 Nov 2026. \nExploitation: There is no known exploitation of CVE-2026-121751 in the wild and no public exploit code.\n\nAffected product: nvm-sh nvm. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-121751/ (Markdown: https://insights.sbomify.com/CVE-2026-121751/index.md)","id":"CVE-2026-121751","markdown":"https://insights.sbomify.com/CVE-2026-121751/index.md","name":"CVE-2026-121751","record":{"aliases":["GHSA-7prg-rw9c-82h7"],"analysis":null,"analysis_generated_by":null,"assigner":"harborist","cpe":[],"cvss":{"score":2.1,"severity":"low","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-78","name":"Improper Neutralization of Special Elements used in an OS Command"},{"id":"CWE-20","name":"Improper Input Validation"}],"description":"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.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":false,"headline":"nvm evaluates a malicious mirror's index.tab version strings as shell arithmetic via stored LTS aliases","id":"CVE-2026-121751","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":null,"year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"Ashlar-Vellum Cobalt LI File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability","id":"CVE-2026-121752"},"nickname":null,"packages":[],"prev":{"headline":"nvm install --offline installs a cached tarball that previously failed checksum verification","id":"CVE-2026-121750"},"products":["nvm"],"published":"2026-11-04","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-11-09","vendors":["nvm-sh"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-121751/"}