This issue looks similar to  bug 817886 , hence assigning to same dev for more updates on it.

yosin@- Could you please take a look in to this issue?

Thanks!

ClusterFuzz has detected this issue as fixed in range 547798:549080.

Detailed report: https://clusterfuzz.com/testcase?key=6302045695639552

Fuzzer: attekett_dom_fuzzer
Job Type: linux_cfi_chrome
Platform Id: linux

Crash Type: Null-dereference READ
Crash Address: 0x000000000010
Crash State:
  chrome
  blink::Node::UpdateDistribution
  blink::ComparePositions
  
Sanitizer: cfi (CFI)

Regressed: https://clusterfuzz.com/revisions?job=linux_cfi_chrome&range=540130:540137
Fixed: https://clusterfuzz.com/revisions?job=linux_cfi_chrome&range=547798:549080

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=6302045695639552

See https://github.com/google/clusterfuzz-tools 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 6302045695639552 is verified as fixed, so closing issue as verified.

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