Predator and CL did not provide any possible suspects.
Using Code Search for the file, "cxfa_node.cpp" assigning to the concern owner.
Suspecting Commit#
https://pdfium.googlesource.com/pdfium.git/+/5fa4e981ed6c431d86c51a74eba19ea4b816f541

@dsinclair -- Could you please look into the issue, kindly re-assign if it has nothing to do with your changes.
Thank You.

ClusterFuzz has detected this issue as fixed in range 462360:462370.

Detailed report: https://clusterfuzz.com/testcase?key=6345759852331008

Fuzzer: libfuzzer_pdfium_xfa_fuzzer
Job Type: libfuzzer_chrome_asan_debug
Platform Id: linux

Crash Type: ASSERT
Crash Address: 
Crash State:
  false
  CXFA_Node::InsertChild
  CXFA_SimpleParser::ParseAsXDPPacket_XDP
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan_debug&range=462343:462360
Fixed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan_debug&range=462360:462370

Reproducer Testcase: https://clusterfuzz.com/download/AMIfv94ZCDzjRMxvMEf-8z0rkWHiTYMxvkbjeJj_c6aFRkhB89yE8PZzkzabL1FGw7Jmy6Nh0l4NxCZf9Xq7xeNnplSrJ4pm58PfUKqGg88pIJllmLAJ5ZwWoipXv7dPPFY6KJp7v8pm5ZcpJ_JQNh5KTwbcsNbIFMxfAT-Hs1dn7zWqNeuUZGziU7fE161fJ8f41DJeQLH-0oaoOh---VRg0dK6YP0Tk3712cKSOwu9FOtRMF-SbxaQ2lrHavq0jJlwWjzIizHxLDvfZYPmig_kcoPeJt7sCENzpdWhYyl-IULkWnewjTwXtlLtvWfnj8RSNyhmoxRUjZnvm72kpkSrJZNrBROH5yBJ13JSH_EmcntGnlBiuL4UY61komnVgExpMPL1fBgPxjtmMqDbR_ja5Nc9ti6nvw?testcase_id=6345759852331008


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 6345759852331008 is verified as fixed, so closing issue.

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

XFA issue.

Bulk-WontFixing these bugs. This was a bug on ClusterFuzz side, see bug 717534. We will start seeing new testcases auto-filed in a day or two. We can't leave these open as ClusterFuzz won't autoverify them after ClusterFuzz-Wrong label.

We have made a bunch of changes on ClusterFuzz side, so resetting ClusterFuzz-Wrong label.