As per the  Issue 767337  owner, assigning this issue to @rharrison.
@rharrison-- Could you please look into this issue, kindly reassign if it has nothing to do with your changes.
Thanks.

npm, could you take a look at this? dsinclair suggested you might have a little more context on the jbig2 code.

The following revision refers to this bug:
  https://pdfium.googlesource.com/pdfium/+/7055dffad92bd7be7cdb20ed12d5cc5890177e7a

commit 7055dffad92bd7be7cdb20ed12d5cc5890177e7a
Author: Nicolas Pena <npm@chromium.org>
Date: Wed Nov 08 17:39:12 2017

Prevent cyclic offset on CJBig2_Context

This CL changes the type of |m_dwOffset| to safe unsigned integer to
prevent the offset from cycling from MAX_UINT32 back to 0.

Bug:  chromium:778912 
Change-Id: Ib93a8392e52eecf2cc223438ac85e9dc529b0f43
Reviewed-on: https://pdfium-review.googlesource.com/18130
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>

[modify] https://crrev.com/7055dffad92bd7be7cdb20ed12d5cc5890177e7a/core/fxcodec/jbig2/JBig2_Context.h
[modify] https://crrev.com/7055dffad92bd7be7cdb20ed12d5cc5890177e7a/core/fxcodec/jbig2/JBig2_Context.cpp

Please note that MSan has a bigger memory overhead compared to other sanitizers (ASan / UBSan). Due to that, it can be hard to fix an OOM happening with MSan.

Yes, but this one is fixed. Re-running CF.

ClusterFuzz has detected this issue as fixed in range 514858:514905.

Detailed report: https://clusterfuzz.com/testcase?key=5002063724675072

Fuzzer: libFuzzer_pdf_codec_jbig2_fuzzer
Job Type: libfuzzer_chrome_msan
Platform Id: linux

Crash Type: Out-of-memory (exceeds 2048 MB)
Crash Address: 
Crash State:
  pdf_codec_jbig2_fuzzer
  
Sanitizer: memory (MSAN)

Regressed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_msan&range=511806:511819
Fixed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_msan&range=514858:514905

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5002063724675072

See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reference.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 5002063724675072 is verified as fixed, so closing issue as verified.

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