lodash vulnerable to prototype pollution via array-path bypass in `_.unset`, `_.omit`, and `_.pullAt

Impact

The _.unset, _.omit, and _.pullAt functions are vulnerable to prototype pollution. The fix for CVE-2025-13465 only guards against string key members, so an attacker can bypass the check by passing array-wrapped path segments. This allows deletion of properties from built-in prototypes such as Object.prototype, Number.prototype, and String.prototype.

The issue permits deletion of prototype properties but does not allow overwriting their original behavior.

Patches

The issue is patched from 4.18.0 to 4.18.1 depending on the package: lodash, lodash-es, and lodash-amd in 4.18.1, and the standalone lodash.unset and lodash.omit packages in 4.18.0.

Workarounds

None. Upgrade to the patched version.

References

• CVE-2025-13465 / GHSA-xxjr-mmjv-4gpg (original fix that this bypasses)