OSV-2026-595 UNKNOWN WRITE in std::__1::istreambuf_iterator<char, std::__1::char_traits<char>> std::__1::num_g

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=504141064 Crash type: UNKNOWN WRITE Crash state: std::1::istreambufiterator std::1::numg std::1::basicistream& std::1::inputar igl::MshLoader::parseelementfield...