CVE-2026-82393 in pnpm
Summary
by MITRE • 08/31/2026
pnpm is a package manager. Prior to 10.34.5 and 11.11.0, pnpm accepts a scoped path traversal in a tarball dependency's package.json manifest name because pnpm11/resolving/npm-resolver/src/pickPackage.ts rejects slash characters only for unscoped names. During pnpm install, the unvalidated name reaches raw path joins in pnpm11/installing/deps-resolver/src/resolvePeers.ts, pnpm11/installing/deps-resolver/src/index.ts, and pnpm11/deps/graph-builder/src/lockfileToDepGraph.ts, causing package extraction outside node_modules and allowing attacker-controlled files to overwrite arbitrary filesystem paths even when --ignore-scripts is used. The overwrite can replace shell startup files, Git hooks, or installed package code and lead to code execution. This issue is fixed in versions 10.34.5, and 11.11.0.
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Analysis
by VulDB Data Team • 08/31/2026
The vulnerability identified involves a critical path traversal flaw within the pnpm package manager, specifically affecting versions prior to 10.34.5 and 11.11.0. This security issue stems from an insufficient validation mechanism in the npm resolver component of pnpm. When processing scoped dependency names during installation, the software fails to adequately sanitize input that contains slash characters within the package name field of a tarball's manifest. While unscoped names are subject to stricter filtering that rejects slashes, scoped packages bypass this check due to logical inconsistencies in the resolution logic located in the pickPackage module. This oversight allows an attacker who controls or influences the metadata of a dependency to inject malicious path sequences into the installation process.
During the execution of pnpm install, the unvalidated package name is passed directly to raw path joining functions within several core modules responsible for resolving peer dependencies and building the lockfile graph. Because these functions do not perform additional normalization or validation on the scoped names they receive, the injected slash characters are interpreted as directory separators rather than literal characters in a filename. This results in the extraction of package contents outside the designated node_modules directory structure. The attacker can thus control the destination path where files from the malicious tarball are written to disk, effectively bypassing the sandboxed environment that pnpm is designed to maintain for dependency isolation.
The operational impact of this vulnerability is severe, as it allows arbitrary file overwrites on the host system with the privileges of the user running the installation command. An attacker can target sensitive configuration files such as shell startup scripts like .bashrc or .zshrc, version control hooks within a Git repository, or critical source code files already present in the project directory. By replacing these files with malicious content, an adversary can achieve persistent remote code execution on the victim's machine. Notably, this exploitation is possible even when the --ignore-scripts flag is used during installation, as the vulnerability relies on file system manipulation rather than script execution hooks within the package manager itself. This makes the attack vector particularly dangerous in automated build environments or CI/CD pipelines where dependencies are frequently installed without interactive oversight.
From a classification perspective, this flaw aligns with CWE-22 Improper Limitation of a Pathname to a Restricted Directory and CWE-73 External Control of File Name or Path. In terms of the MITRE ATT&CK framework, it relates to techniques involving artifact manipulation for persistence and privilege escalation, specifically through file system writes that bypass intended security boundaries. The vulnerability highlights the risks associated with trusting metadata from unverified sources in automated dependency resolution tools.
To mitigate this risk, organizations must immediately upgrade pnpm to version 10.34.5 or later, where the path traversal logic has been corrected to properly sanitize scoped package names and prevent directory escape sequences. For environments that cannot update immediately, it is advisable to audit dependencies for suspicious manifest fields and consider using stricter dependency verification tools such as npm-audit or specialized software composition analysis platforms. Additionally, enforcing least-privilege principles by running build processes under restricted user accounts can limit the potential damage of any successful file overwrite attempts.