Predator and CL did not find any possible suspects.
Using Code Search for the file, "function-body-decoder.cc" assigning to the concern owner.
Suspecting Commit#
https://chromium.googlesource.com/v8/v8.git/+/9fe0b4c7080daf0f52aaabf91ddaf0c6632cfbf8

@bbudge -- Could you please look into the issue, kindly re-assign if this is not related to your changes.
Thank You.

My change introduced new types, but doesn't define default values for them, causing this crash.

ClusterFuzz has detected this issue as fixed in range 452777:452800.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=5846121818882048

Fuzzer: libfuzzer_v8_wasm_asmjs_fuzzer
Job Type: libfuzzer_chrome_msan
Platform Id: linux

Crash Type: Fatal error
Crash Address: 
Crash State:
  
  SignalHandler
  libpthread.so.0
  v8::internal::wasm::WasmFullDecoder::DefaultValue
  
Sanitizer: memory (MSAN)

Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_msan&range=451974:452004
Fixed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_msan&range=452777:452800

Reproducer Testcase: https://cluster-fuzz.appspot.com/download/AMIfv96-4SqskwSV4SjKt6dXibuDzkbpyku90KnTzPpPztGhBvmNQg6w3QPdvlUO0mIMsIoxuQMxiB26YYmN6NLZKYbuqStLj9-RaCAWqLVKqs6y-tSQ2Be3cYxsieiH6PR32ec6Eg3Gh1yUCg3vaIg3kzOTinl9OJgPvuEargMVNcrmpAcFPgG4sMaSUtSju8mmA48LiOEr11ohzNSY3WoIF3C61LLMZBl0k2nxDh_e9kS27H_bInMzf0a7uLdI6TdUtvFkIf_kh-2CYg5MjUeOucLGoCFdMsOWH_j2Fy4OxFDJjt3ndq6z6slCWApr_EGtS7SUEtQC0R95x1HuiNSgn9TsbFmK7LLhyx2HruE3eZJb_ch5QUnLI4wsVZQjE5vghV-da67VspwxduGOUQoDokBHyu5xJA?testcase_id=5846121818882048


See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reproducing.md for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.

ClusterFuzz testcase 5846121818882048 is verified as fixed, so closing issue.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.