OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=42538385
Crash type: Use-of-uninitialized-value
Crash state:
Poco::Dynamic::Var::~Var
void Poco::JSON::Object::doStringify<std::__1::map<std::__1::basic_string<char,
Poco::JWT::Serializer::serialize