CVE-2026-82392

pnpm is a package manager. Prior to 10.34.5 and from 11.0.0 until 11.11.0, pnpm parses the package name from attacker-controlled pnpm-lock.yaml packages keys with dp.parse(depPath).name and uses it without validation in deps/graph-builder/src/lockfileToDepGraph.ts and pnpm11/deps/graph-builder/src/lockfileToDepGraph.ts. The name reaches path.join(modules, pkgName), storeController.importPackage, and pnpm11/lockfile/to-pnp/src/index.ts, allowing package contents to be written outside node_modules when a user runs pnpm install. When dangerouslyAllowAllBuilds or a matching allowBuilds entry permits lifecycle scripts, the escaped package can execute code with the user's privileges. This issue is fixed in versions 10.34.5 and 11.11.0.

pnpm is a package manager. Prior to 10.34.5 and from 11.0.0 until 11.11.0, pnpm parses the package name from attacker-controlled pnpm-lock.yaml packages keys with dp.parse(depPath).name and uses it without validation in deps/graph-builder/src/lockfileToDepGraph.ts and pnpm11/deps/graph-builder/src/lockfileToDepGraph.ts. The name reaches path.join(modules, pkgName), storeController.importPackage, and pnpm11/lockfile/to-pnp/src/index.ts, allowing package contents to be written outside node_modules when a user runs pnpm install. When dangerouslyAllowAllBuilds or a matching allowBuilds entry permits lifecycle scripts, the escaped package can execute code with the user's privileges. This issue is fixed in versions 10.34.5 and 11.11.0.

Summary

The virtual store linker constructs package installation directories using path.join(modules, pkgName) where pkgName is extracted from lockfile packages keys via dp.parse(depPath).name without validation. A crafted pnpm-lock.yaml with traversal sequences in depPath keys (e.g., ../../../tmp/[email protected]) causes package content to be written to arbitrary filesystem paths during pnpm install.

This is an incomplete fix of GHSA-fr4h-3cph-29xv — the safeJoinModulesDir containment helper was applied to the hoisted linker and symlinkDependency but NOT to the virtual store linker's lockfileToDepGraph.ts:233.

Details

Root Cause

dp.parse() at pnpm11/deps/path/src/index.ts:135 extracts the package name as:

const name = dependencyPath.substring(0, sepIndex)

This is a raw substring operation with zero validation that name is a valid npm package name. A depPath of ../../../tmp/[email protected] yields name = '../../../tmp/pwned'.

Vulnerable Code Path

1. pnpm-lock.yaml → lockfile.packages['../../../../../../../tmp/[email protected]'] (attacker-controlled lockfile key)
2. nameVerFromPkgSnapshot(depPath, pkgSnapshot) at lockfile/utils/src/nameVerFromPkgSnapshot.ts:16 → calls dp.parse(depPath) → returns { name: '../../../../../../../tmp/pwned' }
3. lockfileToDepGraph.ts:232 → modules = path.join(dirInVirtualStore, 'node_modules')
4. lockfileToDepGraph.ts:233 → dir = path.join(modules, pkgName) → resolves to /tmp/pwned (ESCAPES virtual store)
5. storeController.importPackage(depNode.dir, ...) → writes package content to the traversed path

Why Existing Defenses Don't Catch It

• depPathToFilename() — replaces / with + for the dirInVirtualStore path, but pkgName comes SEPARATELY from dp.parse() and is NOT passed through this function
• verifyLockfileResolutions() — validates dependency map keys (aliases) via isValidDependencyAlias(), but never validates the depPath keys themselves
• Lockfile parser — yaml.load(lockfileRawContent) with no schema validation on packages keys
• importPackage() — accepts targetDir and passes it directly to cafsStore.importPackage(targetDir, ...) with zero containment check
• Integrity verification — requires a real fetchable package but does not validate the destination path

Escalation to RCE (non-default config)

When dangerouslyAllowAllBuilds: true is configured (or the traversal package name is in the explicit allowBuilds list), the same traversed path is used in the rebuild phase at after-install/src/index.ts:402,470. The attacker's postinstall script then executes with the victim's shell access. Under default config, allowBuild returns false for unknown packages, limiting impact to arbitrary file write.

Also Affected (PnP linker)

When nodeLinker: pnp is configured, lockfileToPackageRegistry() at lockfile/to-pnp/src/index.ts:105-110 uses the same unvalidated dp.parse().name in packageLocation construction, allowing the .pnp.cjs resolver map to point outside the virtual store. This is a lower-impact variant (PnP is not the default linker).

Impact

An attacker who can commit a crafted pnpm-lock.yaml to a repository (or supply one via a malicious package) can cause arbitrary file writes on the machine of any user who runs pnpm install. Written content is the actual package files from a real npm package (attacker controls which package and which destination).

Targets for arbitrary file write include:

• .git/hooks/pre-commit — code execution on next git operation
• ~/.local/bin/ — binary hijacking
• Project source files — supply chain injection

Reproduction

Craft a pnpm-lock.yaml:

lockfileVersion: '9.0'
packages:
  ../../../../../../../tmp/[email protected]:
    resolution: {integrity: sha512-<real-package-integrity>}
    engines: {node: '>=14'}
snapshots:
  ../../../../../../../tmp/[email protected]:…

pnpm is a package manager. Prior to 10.34.5 and from 11.0.0 until 11.11.0, pnpm parses the package name from attacker-controlled pnpm-lock.yaml packages keys with dp.parse(depPath).name and uses it without validation in deps/graph-builder/src/lockfileToDepGraph.ts and pnpm11/deps/graph-builder/src/lockfileToDepGraph.ts. The name reaches path.join(modules, pkgName), storeController.importPackage, and pnpm11/lockfile/to-pnp/src/index.ts, allowing package contents to be written outside node_modules when a user runs pnpm install. When dangerouslyAllowAllBuilds or a matching allowBuilds entry permits lifecycle scripts, the escaped package can execute code with the user's privileges. This issue is fixed in versions 10.34.5 and 11.11.0.

pnpm is a package manager. Prior to 10.34.5 and from 11.0.0 until 11.11.0, pnpm parses the package name from attacker-controlled pnpm-lock.yaml packages keys with dp.parse(depPath).name and uses it without validation in deps/graph-builder/src/lockfileToDepGraph.ts and pnpm11/deps/graph-builder/src/lockfileToDepGraph.ts. The name reaches path.join(modules, pkgName), storeController.importPackage, and pnpm11/lockfile/to-pnp/src/index.ts, allowing package contents to be written outside node_modules when a user runs pnpm install. When dangerouslyAllowAllBuilds or a matching allowBuilds entry permits lifecycle scripts, the escaped package can execute code with the user's privileges. This issue is fixed in versions 10.34.5 and 11.11.0.

Summary

The virtual store linker constructs package installation directories using path.join(modules, pkgName) where pkgName is extracted from lockfile packages keys via dp.parse(depPath).name without validation. A crafted pnpm-lock.yaml with traversal sequences in depPath keys (e.g., ../../../tmp/[email protected]) causes package content to be written to arbitrary filesystem paths during pnpm install.

This is an incomplete fix of GHSA-fr4h-3cph-29xv — the safeJoinModulesDir containment helper was applied to the hoisted linker and symlinkDependency but NOT to the virtual store linker's lockfileToDepGraph.ts:233.

Details

Root Cause

dp.parse() at pnpm11/deps/path/src/index.ts:135 extracts the package name as:

const name = dependencyPath.substring(0, sepIndex)

This is a raw substring operation with zero validation that name is a valid npm package name. A depPath of ../../../tmp/[email protected] yields name = '../../../tmp/pwned'.

Vulnerable Code Path

1. pnpm-lock.yaml → lockfile.packages['../../../../../../../tmp/[email protected]'] (attacker-controlled lockfile key)
2. nameVerFromPkgSnapshot(depPath, pkgSnapshot) at lockfile/utils/src/nameVerFromPkgSnapshot.ts:16 → calls dp.parse(depPath) → returns { name: '../../../../../../../tmp/pwned' }
3. lockfileToDepGraph.ts:232 → modules = path.join(dirInVirtualStore, 'node_modules')
4. lockfileToDepGraph.ts:233 → dir = path.join(modules, pkgName) → resolves to /tmp/pwned (ESCAPES virtual store)
5. storeController.importPackage(depNode.dir, ...) → writes package content to the traversed path

Why Existing Defenses Don't Catch It

• depPathToFilename() — replaces / with + for the dirInVirtualStore path, but pkgName comes SEPARATELY from dp.parse() and is NOT passed through this function
• verifyLockfileResolutions() — validates dependency map keys (aliases) via isValidDependencyAlias(), but never validates the depPath keys themselves
• Lockfile parser — yaml.load(lockfileRawContent) with no schema validation on packages keys
• importPackage() — accepts targetDir and passes it directly to cafsStore.importPackage(targetDir, ...) with zero containment check
• Integrity verification — requires a real fetchable package but does not validate the destination path

Escalation to RCE (non-default config)

When dangerouslyAllowAllBuilds: true is configured (or the traversal package name is in the explicit allowBuilds list), the same traversed path is used in the rebuild phase at after-install/src/index.ts:402,470. The attacker's postinstall script then executes with the victim's shell access. Under default config, allowBuild returns false for unknown packages, limiting impact to arbitrary file write.

Also Affected (PnP linker)

When nodeLinker: pnp is configured, lockfileToPackageRegistry() at lockfile/to-pnp/src/index.ts:105-110 uses the same unvalidated dp.parse().name in packageLocation construction, allowing the .pnp.cjs resolver map to point outside the virtual store. This is a lower-impact variant (PnP is not the default linker).

Impact

An attacker who can commit a crafted pnpm-lock.yaml to a repository (or supply one via a malicious package) can cause arbitrary file writes on the machine of any user who runs pnpm install. Written content is the actual package files from a real npm package (attacker controls which package and which destination).

Targets for arbitrary file write include:

• .git/hooks/pre-commit — code execution on next git operation
• ~/.local/bin/ — binary hijacking
• Project source files — supply chain injection

Reproduction

Craft a pnpm-lock.yaml:

lockfileVersion: '9.0'
packages:
  ../../../../../../../tmp/[email protected]:
    resolution: {integrity: sha512-<real-package-integrity>}
    engines: {node: '>=14'}
snapshots:
  ../../../../../../../tmp/[email protected]:…