CVE-2026-55698VulnerabilityPublished 13 Aug 2026Updated 26 Oct 2026

pnpm@10 · pnpm: Project env lockfile can short-circuit package-manager resolution and execute lockfile-selected pnpm bytes

Affects pnpm@10Source GCVE Database

Not known to be exploited · CVSS 8.8 High : upgrade to 10.34.2 soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

8.8High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 22% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 10.34.2

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade pnpm@10 to 10.34.2.

Affected software

Product	Affected	Fixed in
Homebrewpnpm@10`pkg:brew/pnpm%4010`Other threats	Affected >=10.33.2 <10.34.2	Fixed in 10.34.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

## Maintainer Action Plan This report is ready to review with the shared patch branch. Start with the PR and the expected fixed behavior, then use the detailed exploit narrative below only if you want to replay the original path. - Advisory: `CAND-PNPM-063` / `GHSA-w466-c33r-3gjp` - Advisory URL: https://github.com/pnpm/pnpm/security/advisories/GHSA-w466-c33r-3gjp - Shared patch PR: https://github.com/pnpm/pnpm-ghsa-j2hc-m6cf-6jm8/pull/1 - Shared patch branch: `security/ghsa-batch-2026-06-09` - Patch commit: `a93449314f398cf4bdf2e28d033c02d37395ad22` - Base commit: `origin/main` `55a4035abf1ae3fe7208ba1f5ef43c5eff58ccec` - Maintainer priority: `start-here` - Component: `pnpm packageManager env lockfile` - Patch area: package-manager env lockfile is re-resolved through trusted registries before execution - Affected packages: `npm:pnpm`, `npm:@pnpm/installing.env-installer` - CWE IDs: `CWE-829`, `CWE-494`, `CWE-345` - Conservative CVSS: `8.8` / `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H` - Next action: review the shared patch branch for this component, set the final affected version range, merge and release the fix, then publish or close the advisory. ### Expected Patched Behavior Committed env-lockfile package-manager entries are force-refreshed through trusted registries before execution; attacker tarball requests and markers stay at zero. ### Files And Tests To Review - `installing/env-installer/src/resolvePackageManagerIntegrities.ts` - `pnpm/src/switchCliVersion.ts` - `pnpm/src/switchCliVersion.test.ts` - `.changeset/clean-package-manager-registries.md` ### Focused Validation Run these from a checkout of the shared patch branch. They are the useful maintainer commands with machine-local artifact paths removed. ```bash ./node_modules/.bin/tsgo --build installing/env-installer/tsconfig.json ./node_modules/.bin/tsgo --build pnpm/tsconfig.json PNPM_REGISTRY_MOCK_PORT=7799 NODE_OPTIONS="--experimental-vm-modules --disable-warning=ExperimentalWarning --disable-warning=DEP0169" ../node_modules/.bin/jest src/switchCliVersion.test.ts -t "re-resolved package-manager lockfile" --runInBand PNPM_REGISTRY_MOCK_PORT=7799 NODE_OPTIONS="--experimental-vm-modules --disable-warning=ExperimentalWarning --disable-warning=DEP0169" ../node_modules/.bin/jest src/switchCliVersion.test.ts src/syncEnvLockfile.test.ts --runInBand ./node_modules/.bin/eslint installing/env-installer/src/resolvePackageManagerIntegrities.ts pnpm/src/switchCliVersion.ts pnpm/src/switchCliVersion.test.ts git diff --check ``` The full patched replay for the shared branch passed with all 20 candidates marked fixed. This candidate's replay evidence is `results/CAND-PNPM-063-patched-result.json`.  ### Summary pnpm can persist package-manager bootstrap metadata in the first YAML document of `pnpm-lock.yaml`. Before the patch, direct pnpm execution trusted an already resolved `packageManagerDependencies` entry when the committed env lockfile contained matching `pnpm` and `@pnpm/exe` versions. A malicious repository could therefore commit package-manager lockfile package records and snapshots that bypassed fresh package-manager resolution, then cause pnpm to install and execute bytes selected by that committed lockfile state during automatic version switching. ### Details The vulnerable source-to-sink path was: - `lockfile/fs/src/envLockfile.ts` reads the repository's first YAML lockfile document and validates shape only. - `pnpm/src/main.ts` reaches `switchCliVersion()` when a direct pnpm invocation sees a wanted `pnpm` package manager with `onFail=download`. - `pnpm/src/switchCliVersion.ts` reads the committed env lockfile when package-manager metadata should be persisted. - `installing/env-installer/src/resolvePackageManagerIntegrities.ts` treated `packageManagerDependencies` as resolved when only the `pnpm` and `@pnpm/exe` versions matched. - `engine/pm/commands/src/self-updater/installPnpm.ts` converts env-lockfile `snapshots` and `packages` into the wanted lockfile used by `headlessInstall()`. - `pnpm/src/switchCliVersion.ts` executes the installed `pnpm` binary with `spawn.sync()`. The helper fast path is intentionally still version-based for non-execution callers, so the security boundary is enforced at the execution path: `switchCliVersion()` now re-resolves already present package-manager env-lockfile entries before they can reach `installPnpmToStore()` and `spawn.sync()`. ### PoC Standalone PoC and verification script: The PoC constructs a committed env-lockfile object with matching package-manager dependency versions and attacker-selected package metadata: ```json { "importers": { ".": { "configDependencies": {}, "packageManagerDependencies": { "@pnpm/exe": { "specifier": "9.3.0", "version": "9.3.0" }, "pnpm": { "specifier": "9.3.0", "version": "9.3.0" } } } }, "lockfileVersion": "9.0", "packages": { "/pnpm@9.3.

References

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