{"id":"CVE-2026-15921","state":"PUBLISHED","title":"nvm path traversal via a malicious mirror's LTS codename writes outside the alias directory","description":"Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.32.1 through 0.40.5, `nvm ls-remote` (and other commands that refresh remote LTS aliases, such as `nvm install --lts`) parse the node.js mirror's `index.tab` and use each release's LTS codename field as an alias filename without validating it. A malicious, compromised, or man-in-the-middled mirror can return an LTS codename containing path-traversal sequences such as `../../../.bashrc`, causing nvm to write the associated version string to a path outside `$NVM_DIR/alias`. With the default layout (`$NVM_DIR` is `~/.nvm`), this can create or overwrite files in the user's home directory, including shell startup files, which can lead to code execution in a later shell session. Exploitation requires the victim to use a hostile mirror -- via a compromised mirror or CDN, a network man-in-the-middle, or a maliciously configured `NVM_NODEJS_ORG_MIRROR`/`NVM_IOJS_ORG_MIRROR` -- and to run an affected command. Version 0.40.6 validates remote LTS codenames as safe alias filenames and rejects `..` path components when writing alias files.","publishedAt":"2026-07-15T21:16:46.936Z","updatedAt":"2026-07-16T12:53:35.897Z","severity":{"score":2.1,"label":"Low","version":"4.0","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","source":"harborist"},"assigner":"harborist","products":["nvm-sh nvm"],"affected":[{"vendor":"nvm-sh","product":"nvm","defaultStatus":"unaffected","versions":[{"version":"0.32.1","status":"affected","lessThan":"0.40.6","versionType":"semver"}],"repo":"https://github.com/nvm-sh/nvm"}],"references":["https://github.com/nvm-sh/nvm/security/advisories/GHSA-4ghp-wxpw-rhpg","https://github.com/nvm-sh/nvm/commit/9275c5badda1d9d0cdad6f34598a111033eadb42"],"weaknesses":["CWE-22","CWE-73"],"ingestedAt":"2026-10-29T20:11:00.674Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/15xxx/CVE-2026-15921.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-15921","state":"PUBLISHED","datePublished":"2026-07-15T21:16:46.936Z","dateUpdated":"2026-07-16T12:53:35.897Z","assignerShortName":"harborist","assignerOrgId":"7ffcee3d-2c14-4c3e-b844-86c6a321a158","dateReserved":"2026-07-15T20:49:26.387Z"},"containers":{"cna":{"title":"nvm path traversal via a malicious mirror's LTS codename writes outside the alias directory","descriptions":[{"lang":"en","value":"Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.32.1 through 0.40.5, `nvm ls-remote` (and other commands that refresh remote LTS aliases, such as `nvm install --lts`) parse the node.js mirror's `index.tab` and use each release's LTS codename field as an alias filename without validating it. A malicious, compromised, or man-in-the-middled mirror can return an LTS codename containing path-traversal sequences such as `../../../.bashrc`, causing nvm to write the associated version string to a path outside `$NVM_DIR/alias`. With the default layout (`$NVM_DIR` is `~/.nvm`), this can create or overwrite files in the user's home directory, including shell startup files, which can lead to code execution in a later shell session. Exploitation requires the victim to use a hostile mirror -- via a compromised mirror or CDN, a network man-in-the-middle, or a maliciously configured `NVM_NODEJS_ORG_MIRROR`/`NVM_IOJS_ORG_MIRROR` -- and to run an affected command. Version 0.40.6 validates remote LTS codenames as safe alias filenames and rejects `..` path components when writing alias files."}],"affected":[{"vendor":"nvm-sh","product":"nvm","defaultStatus":"unaffected","versions":[{"version":"0.32.1","status":"affected","lessThan":"0.40.6","versionType":"semver"}],"repo":"https://github.com/nvm-sh/nvm"}],"references":[{"url":"https://github.com/nvm-sh/nvm/security/advisories/GHSA-4ghp-wxpw-rhpg","name":"GHSA-4ghp-wxpw-rhpg","tags":["vendor-advisory"]},{"url":"https://github.com/nvm-sh/nvm/commit/9275c5badda1d9d0cdad6f34598a111033eadb42","name":"Fix commit 9275c5ba","tags":["patch"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"ACTIVE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"LOW","baseScore":2.1,"vectorString":"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"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE","baseSeverity":"LOW","baseScore":3.1,"vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-22","lang":"en","description":"CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-73","lang":"en","description":"CWE-73 External Control of File Name or Path","type":"CWE"}]}],"providerMetadata":{"shortName":"harborist","orgId":"7ffcee3d-2c14-4c3e-b844-86c6a321a158","dateUpdated":"2026-07-15T21:38:53.719Z"},"datePublic":"2026-07-15T00:00:00.000Z","workarounds":[{"lang":"en","value":"Until upgrading, only run `nvm ls-remote` and LTS-refreshing commands against trusted mirrors over TLS, and ensure `NVM_NODEJS_ORG_MIRROR` and `NVM_IOJS_ORG_MIRROR` point only at trusted endpoints.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>Until upgrading, only run `nvm ls-remote` and LTS-refreshing commands against trusted mirrors over TLS, and ensure `NVM_NODEJS_ORG_MIRROR` and `NVM_IOJS_ORG_MIRROR` point only at trusted endpoints.</p>"}]}],"solutions":[{"lang":"en","value":"Upgrade to nvm 0.40.6 or later, which validates remote LTS codenames and rejects `..` path components when writing alias files. (Only needed if using a non-default mirror whose metadata contents you do not trust).","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>Upgrade to nvm 0.40.6 or later, which validates remote LTS codenames and rejects `..` path components when writing alias files. (Only needed if using a non-default mirror whose metadata contents you do not trust).</p>"}]}],"credits":[{"lang":"en","value":"Sy2n0 (https://github.com/Sy2n0)","type":"finder"},{"lang":"en","value":"Jordan Harband (https://github.com/ljharb)","type":"remediation developer"}],"source":{"advisory":"GHSA-4ghp-wxpw-rhpg","discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 1.0.2"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/nvm-sh/nvm/security/advisories/GHSA-4ghp-wxpw-rhpg","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-16T12:53:15.866939Z","id":"CVE-2026-15921","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-16T12:53:35.897Z"}}]}}}