Predator and CL did not provide any possible suspects.
Using Code Search for the file, "fx_memory.h" assigning to the concern owner.
Suspecting Commit#
https://pdfium.googlesource.com/pdfium.git/+/a52ab741019342fbca0468e43a01deb44fa5f1bd

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

Assigning to tsepez@ for when https://pdfium-review.googlesource.com/c/3095/ lands in Chromium.

Presumably same root cause as 702064, CF will re-open if not the case.

ClusterFuzz has detected this issue as fixed in range 457505:457874.

Detailed report: https://clusterfuzz.com/testcase?key=5865296608100352

Fuzzer: libfuzzer_pdfium_fuzzer
Job Type: libfuzzer_chrome_asan
Platform Id: linux

Crash Type: Indirect-leak
Crash Address: 
Crash State:
  FX_AllocOrDie
  CPDF_SyntaxParser::InitParser
  CPDF_DataAvail::IsLinearizedFile
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan&range=431756:431777
Fixed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan&range=457505:457874

Reproducer Testcase: https://clusterfuzz.com/download/AMIfv96DbG9VXvDftQU1AnsoNVQFdd-eWWAQgjzJBoZ-kT4mBD4cqVoOCrOG47VkSXwwmeBYRTX3YCvAPV333fILUvvdjlFx9ksiSycGolKKNU3_A5DOpqAwnn3f1nStkKdt-OsjHQWvKocaBtpvWSbFpIydwP-xhRMsid7qKPwej8JU-l6CO7D2SM10VoouPnqczt4Xx8W99YfYTW-zLx5_Wny3SnPRRaGFXa59kqnD56t-CcfcGu1MDSBwFT9f-ZMJZhbzkQwpx0lwjtINSXDHqEXChHNycBGYy3A1dvKGEz-t57WHG-CGYqmu9PyNJ-ZC2cyVsqnCmU3z3xF3l1P7Swc9Ui4AZWxC7tQbW-jlp69AhbJdTJw?testcase_id=5865296608100352


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 has detected this issue as fixed in range 457505:457874.

Detailed report: https://clusterfuzz.com/testcase?key=5865296608100352

Fuzzer: libfuzzer_pdfium_fuzzer
Job Type: libfuzzer_chrome_asan
Platform Id: linux

Crash Type: Indirect-leak
Crash Address: 
Crash State:
  FX_AllocOrDie
  CPDF_SyntaxParser::InitParser
  CPDF_DataAvail::IsLinearizedFile
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan&range=431756:431777
Fixed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan&range=457505:457874

Reproducer Testcase: https://clusterfuzz.com/download/AMIfv96DbG9VXvDftQU1AnsoNVQFdd-eWWAQgjzJBoZ-kT4mBD4cqVoOCrOG47VkSXwwmeBYRTX3YCvAPV333fILUvvdjlFx9ksiSycGolKKNU3_A5DOpqAwnn3f1nStkKdt-OsjHQWvKocaBtpvWSbFpIydwP-xhRMsid7qKPwej8JU-l6CO7D2SM10VoouPnqczt4Xx8W99YfYTW-zLx5_Wny3SnPRRaGFXa59kqnD56t-CcfcGu1MDSBwFT9f-ZMJZhbzkQwpx0lwjtINSXDHqEXChHNycBGYy3A1dvKGEz-t57WHG-CGYqmu9PyNJ-ZC2cyVsqnCmU3z3xF3l1P7Swc9Ui4AZWxC7tQbW-jlp69AhbJdTJw?testcase_id=5865296608100352


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.