GHSA-fm67-cv37-96ff

### Impact _What kind of vulnerability is it? Who is impacted?_

When an error occurs while reallocating the buffer for string decoding, the buffer gets freed twice.

Due to how UltraJSON uses the internal decoder, this double free is impossible to trigger from Python.

### Patches _Has the problem been patched? What versions should users upgrade to?_

Users should upgrade to UltraJSON 5.4.0.

### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_

There is no workaround.

### For more information If you have any questions or comments about this advisory: * Open an issue in [UltraJSON](http://github.com/ultrajson/ultrajson/issues)