Through code search on file cfx_seekablestreamproxy.cpp, suspected CL is 
https://pdfium.googlesource.com/pdfium.git/+/283a0433b081f88275b2f7e8c04d3c41b9187ca6%5E%21/#F7
dsinclair@, could you please take a look?.
Thank you.

ClusterFuzz has detected this issue as fixed in range 467638:467652.

Detailed report: https://clusterfuzz.com/testcase?key=5663337437462528

Fuzzer: libfuzzer_pdf_xml_fuzzer
Job Type: libfuzzer_chrome_asan_debug
Platform Id: linux

Crash Type: ASSERT
Crash Address: 
Crash State:
  pBuffer && iLength > 0
  UTF16ToWChar
  CFX_SeekableStreamProxy::ReadString
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan_debug&range=467627:467638
Fixed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan_debug&range=467638:467652

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5663337437462528


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 5663337437462528 is verified as fixed, so closing issue.

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

We need to verify if this is fixed.

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.