Predator and CL could not provide any possible suspects.
Using Code Search for the file, "PublicMethods.cpp" assigning to concern owner.

Suspecting Commit#
https://pdfium.googlesource.com/pdfium.git/+/df950b87e781daf92364afb22f13d87b18858c80

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

Need to check for zero-length string now at https://pdfium.googlesource.com/pdfium/+/d3002340caad8d688d0e4928a36e90d354a797bd/fpdfsdk/javascript/PublicMethods.cpp#1765

Thanks for the analysis tsepez.

The following revision refers to this bug:
  https://pdfium.googlesource.com/pdfium/+/75c65210c59de575f5a536f53bab9018b6edbed9

commit 75c65210c59de575f5a536f53bab9018b6edbed9
Author: Ryan Harrison <rharrison@chromium.org>
Date: Wed Aug 16 18:48:31 2017

Add in missting string length check

BUG= chromium:754984 

Change-Id: I106d460c80804797cee537d1990f901b5bf5a519
Reviewed-on: https://pdfium-review.googlesource.com/11171
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

[modify] https://crrev.com/75c65210c59de575f5a536f53bab9018b6edbed9/fpdfsdk/javascript/PublicMethods.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/27ec0b7c12ce7e2e231cc7955f2946fe6915d897

commit 27ec0b7c12ce7e2e231cc7955f2946fe6915d897
Author: pdfium-deps-roller@chromium.org <pdfium-deps-roller@chromium.org>
Date: Wed Aug 16 20:51:01 2017

Roll src/third_party/pdfium/ ca8982977..a169364e4 (7 commits)

https://pdfium.googlesource.com/pdfium.git/+log/ca89829775fe..a169364e4695

$ git log ca8982977..a169364e4 --date=short --no-merges --format='%ad %ae %s'
2017-08-16 rharrison Add parse depth limit to FormCalc parser
2017-08-16 rharrison Add in missting string length check
2017-08-16 thestig Fix potential OOM / integer overflow in CPDF_Parser.
2017-08-14 tsepez Check for possible empty object returns from NewFxDynamicObj()
2017-08-16 janeliulwq Fixed the return values of FPDFAnnot_Get{Rect|AttachmentPoints}
2017-08-16 dsinclair Remove CFWL_WidgetMgrDelegate
2017-08-15 janeliulwq Changed the return type of FPDFAnnot_Get{Rect|AttachmentPoints}()

Created with:
  roll-dep src/third_party/pdfium
BUG= 752433 , 754984 , 752796 


Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, see:
http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium#TOC-Failures-due-to-DEPS-rolls


TBR=dsinclair@chromium.org

Change-Id: I1a6f55adde2f82919d1e644a9f1ccd5c301bba29
Reviewed-on: https://chromium-review.googlesource.com/617402
Reviewed-by: <pdfium-deps-roller@chromium.org>
Commit-Queue: <pdfium-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#494941}
[modify] https://crrev.com/27ec0b7c12ce7e2e231cc7955f2946fe6915d897/DEPS

ClusterFuzz has detected this issue as fixed in range 494865:494953.

Detailed report: https://clusterfuzz.com/testcase?key=6368826139869184

Fuzzer: ifratric_pdf_generic
Job Type: mac_asan_chrome
Platform Id: mac

Crash Type: Null-dereference READ
Crash Address: 0x000000000010
Crash State:
  CJS_PublicMethods::AFExtractNums
  void JSGlobalFunc<&
  v8::internal::FunctionCallbackArguments::Call
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=mac_asan_chrome&range=493959:493966
Fixed: https://clusterfuzz.com/revisions?job=mac_asan_chrome&range=494865:494953

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=6368826139869184

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 6368826139869184 is verified as fixed, so closing issue as verified.

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