Time-of-check Time-of-use (TOCTOU) Race Condition
The package integrity validation in yarn before 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.
CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
The software checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the software to perform invalid actions when the resource is in an unexpected state.