{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-121751", "assignerOrgId": "7ffcee3d-2c14-4c3e-b844-86c6a321a158", "state": "PUBLISHED", "assignerShortName": "harborist", "dateReserved": "2026-11-03T23:39:04.553Z", "datePublished": "2026-11-04T21:26:57.967Z", "dateUpdated": "2026-11-04T21:26:57.967Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "7ffcee3d-2c14-4c3e-b844-86c6a321a158", "shortName": "harborist", "dateUpdated": "2026-11-04T21:26:57.967Z"}, "title": "nvm evaluates a malicious mirror's index.tab version strings as shell arithmetic via stored LTS aliases", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-78", "description": "CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')", "type": "CWE"}]}, {"descriptions": [{"lang": "en", "cweId": "CWE-20", "description": "CWE-20 Improper Input Validation", "type": "CWE"}]}], "affected": [{"vendor": "nvm-sh", "product": "nvm", "repo": "https://github.com/nvm-sh/nvm", "versions": [{"status": "affected", "version": "0.39.6", "lessThan": "0.41.0", "versionType": "semver"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "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[$(cmd)1]` runs `cmd` as the user when the alias is later resolved by purely local commands (`nvm ls`, `nvm alias`, `nvm use --lts`, `nvm which lts/`), and in every new shell when the `default` alias is `lts/*`. Exploitation requires the victim to use a hostile mirror -- via a compromised mirror or CDN, a network man-in-the-middle of an `http://` mirror, or a maliciously configured `NVM_NODEJS_ORG_MIRROR` -- and to run an affected command. The same sink is also reachable from a project `.nvmrc`, which is treated as hardening. dash is not affected. Version 0.41.0 only passes an all-digit `lts/-N` offset to arithmetic and drops `index.tab` rows whose version is not a valid version string.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Node Version Manager (nvm) is a POSIX-compliant shell function for managing multiple node.js versions. In versions 0.39.6 through 0.40.8, `nvm ls-remote` (and other commands that refresh remote LTS aliases) store the version column of the mirror's `index.tab` in `$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.</p>"}]}], "references": [{"url": "https://github.com/nvm-sh/nvm/security/advisories/GHSA-7prg-rw9c-82h7", "name": "GHSA-7prg-rw9c-82h7", "tags": ["vendor-advisory"]}, {"url": "https://github.com/nvm-sh/nvm/commit/aa0572b7c48b2652a9f86276bbbf3840939981af", "name": "Fix commit aa0572b7", "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"}}], "workarounds": [{"lang": "en", "value": "Until upgrading, only run `nvm ls-remote` and LTS-refreshing commands against trusted mirrors over TLS, ensure `NVM_NODEJS_ORG_MIRROR` points only at a trusted endpoint, and do not run nvm in untrusted project directories.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Until upgrading, only run `nvm ls-remote` and LTS-refreshing commands against trusted mirrors over TLS, ensure `NVM_NODEJS_ORG_MIRROR` points only at a trusted endpoint, and do not run nvm in untrusted project directories.</p>"}]}], "solutions": [{"lang": "en", "value": "Upgrade to nvm 0.41.0 or later, which only lets an all-digit `lts/-N` offset reach shell arithmetic and drops mirror rows with invalid version strings. (Only needed if using a non-default mirror whose metadata contents you do not trust, or running nvm in untrusted project directories.)", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Upgrade to nvm 0.41.0 or later, which only lets an all-digit `lts/-N` offset reach shell arithmetic and drops mirror rows with invalid version strings. (Only needed if using a non-default mirror whose metadata contents you do not trust, or running nvm in untrusted project directories.)</p>"}]}], "credits": [{"lang": "en", "value": "Anthropic's OSS Scanner, as vulnerabilities ANT-2026-0GXXE91V and ANT-2026-31ZIEY85", "type": "finder"}, {"lang": "en", "value": "Adel Assakaf (https://github.com/assakafpix)", "type": "finder"}, {"lang": "en", "value": "Jordan Harband (https://github.com/ljharb)", "type": "remediation developer"}], "source": {"advisory": "GHSA-7prg-rw9c-82h7", "discovery": "EXTERNAL"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "nvm", "repo": "https://github.com/nvm-sh/nvm", "vendor": "nvm-sh", "versions": [{"lessThan": "0.41.0", "status": "affected", "version": "0.39.6", "versionType": "semver"}]}], "source": "7ffcee3d-2c14-4c3e-b844-86c6a321a158"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-121751", "lastModified": "2026-11-04T22:17:55.060", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 3.1, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 1.6, "impactScore": 1.4, "source": "7ffcee3d-2c14-4c3e-b844-86c6a321a158", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 2.1, "baseSeverity": "LOW", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "ACTIVE", "valueDensity": "NOT_DEFINED", "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "7ffcee3d-2c14-4c3e-b844-86c6a321a158", "type": "Secondary"}]}, "published": "2026-11-04T22:17:55.060", "references": [{"source": "7ffcee3d-2c14-4c3e-b844-86c6a321a158", "url": "https://github.com/nvm-sh/nvm/commit/aa0572b7c48b2652a9f86276bbbf3840939981af"}, {"source": "7ffcee3d-2c14-4c3e-b844-86c6a321a158", "url": "https://github.com/nvm-sh/nvm/security/advisories/GHSA-7prg-rw9c-82h7"}], "sourceIdentifier": "7ffcee3d-2c14-4c3e-b844-86c6a321a158", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-78"}], "source": "7ffcee3d-2c14-4c3e-b844-86c6a321a158", "type": "Secondary"}]}

{}

{}