CVE-2026-50573 — pnpm: Unsafe default behavior breaks integrity check

Affected: pnpm

pnpm is a package manager. Prior to 10.34.0 and 11.4.0, `pnpm install` in non-frozen mode can accept new remote package content after detecting that the downloaded tarball does not match the integrity recorded in pnpm-lock.yaml. When a package is already locked with an integrity value, and the registry later serves different metadata and tarball content for the same package name and version, pnpm initially reports an integrity mismatch. However, plain pnpm install then performs a resolution repair, accepts the registry's new integrity, updates the lockfile, installs the new content, and exits successfully. This means the lockfile integrity check does not act as a hard stop by default. This vulnerability is fixed in 10.34.0 and 11.4.0.

GHSA-54hh-g5mx-jqcp — pnpm: Unsafe default behavior breaks integrity check

Affected: npm: pnpm

While it is unclear whether this should be classified as a vulnerability, it is being reported through this channel because the current behavior may represent an unsafe default.

## Summary

`pnpm install` in non-frozen mode can accept new remote package content after detecting that the downloaded tarball does not match the integrity recorded in `pnpm-lock.yaml`.

When a package is already locked with an `integrity` value, and the registry later serves different metadata and tarball content for the same package name and version, pnpm initially reports an integrity mismatch. However, plain `pnpm install` then performs a resolution repair, accepts the registry's new integrity, updates the lockfile, installs the new content, and exits successfully.

This means the lockfile integrity check does not act as a hard stop by default.

## Reproduction Scenario

1. Run a local npm-compatible registry. 2. Publish or serve `example-package@1.0.0` with tarball content `v1`. 3. Install it with pnpm:

```bash pnpm add example-package@1.0.0 --registry=http://127.0.0.1:48741 ```

4. Confirm `pnpm-lock.yaml` contains the `v1` integrity:

```yaml packages: example-package@1.0.0: resolution: integrity: sha512-...v1... ```

5. Change the registry metadata and tarball for the same `example-package@1.0.0` to content `v2`. 6. On a clean store/cache, run:

```bash pnpm install --registry=http://127.0.0.1:48741 ```

## Observed Behavior

pnpm detects the checksum mismatch:

```text WARN Go…

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CVE-2026-50573 — pnpm: Unsafe default behavior breaks integrity check

GHSA-54hh-g5mx-jqcp — pnpm: Unsafe default behavior breaks integrity check