Predator and CL did not provide any possible suspects.
Using Code Search for the file, "cpdf_simplefont.cpp" assigning to the concern owner.
Suspecting Commit#
https://pdfium.googlesource.com/pdfium.git/+/169b30187bf5798a6106b5ab16288c9d86861f8b

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

Re-running because I can't reproduce and the crash error doesn't make sense from the stack trace (this was recently fixed).

Clusterfuzz will say it's fixed once it actually compiles.

ClusterFuzz has detected this issue as fixed in range 476905:485054.

Detailed report: https://clusterfuzz.com/testcase?key=4836911624749056

Fuzzer: libFuzzer_pdf_font_fuzzer
Job Type: mac_libfuzzer_chrome_asan
Platform Id: mac

Crash Type: Ill
Crash Address: 0x00010b03d4c9
Crash State:
  int pdfium::base::CheckOnFailure::HandleFailure<int>
  CPDF_SimpleFont::LoadCharMetrics
  CPDF_SimpleFont::GetCharBBox
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=mac_libfuzzer_chrome_asan&range=472872:472906
Fixed: https://clusterfuzz.com/revisions?job=mac_libfuzzer_chrome_asan&range=476905:485054

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=4836911624749056


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.