An untrusted search path vulnerability was found in Yarn. When a victim runs certain Yarn commands in a directory with attacker-controlled content, malicious commands could be executed in unexpected ways.

The package integrity validation in yarn < 1.19.0 contains a TOCTOU vulnerability where the hash is computed before writing a package to cache. It's not computed again when reading from the cache. This may lead to a cache pollution attack.

Arbitrary filesystem write vulnerability in Yarn before 1.22.0 allows attackers to write to any path on the filesystem and potentially lead to arbitrary code execution by forcing the user to install a malicious package.

In Yarn before 1.21.1, the package install functionality can be abused to generate arbitrary symlinks on the host filesystem by using specially crafted "bin" keys. Existing files could be overwritten depending on the current user permission set.

Yarn before 1.17.3 is vulnerable to Missing Encryption of Sensitive Data due to HTTP URLs in lockfile causing unencrypted authentication data to be sent over the network.