Some of these files are the devil's work!

Stressful PDF corpus grows!

Peter Wyatt // November 12, 2020


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In early September I announced the initial release of the “Issue Tracker” stressful corpus of PDF files that was developed under the DARPA-funded “SafeDocs” program. This has generated a lot of interest in the PDF technical community, and we have received some great feedback from many early adopters.

Now version 2 of the “Issue Tracker” corpus of stressful PDF has landed just 2 months later!

From the original 11 issue tracker repositories the corpus now includes bug attachment data from 35 issue tracker repositories across 32 PDF technologies, comprising 31GB and over 32,500 stressful PDF files.

This large increase in issue trackers now spans a broader variety of PDF technologies written in a wider range of programming languages and, as one might expect, follows some technologies between issue trackers. Due to this increase in size, we have re-packaged the corpus into six compressed tar balls (.tgz files) each containing the data from multiple repositories to make downloading more convenient.

PDF technology Folder Issue Tracker URL # files Size .tgz file)
Android PDF Viewer (Java) androidpdfviewer 13 3.2M 5
Cairo cairo 166 33M 5
Cairo cairo-gitlab 29 12M 6
DeJaVu dejavu 39 2.7M 5
eSignature DSS DSS 243 89M 5
GNOME Evince evince 241 591M 6
Apache FOP FOP 808 157M 5
GhostScript (C/C++) GHOSTSCRIPT 5,458 5.6G 2
Snappy PDF (laravel, PHP) laravel-snappy 5 1.8M 5
Libre Office LIBRE_OFFICE 5,572 1.4G 4
libvips image library libvips 18 384M 5
Mozilla MOZILLA 6,879 3.9G 3
Apache Nutch NUTCH 13 976K 5
OCRmyPDF (Python) ocrmypdf 205 501M 5
Apache OOO 1,564 253M 4
OpenPDF (Java) openpdf 32 3.2M 5
parsr (JS) parsr 28 12M 5
Mozilla pdf.js (JS) pdf.js 2,368 4.5G 4
Apache PDFBOX (Java) PDFBOX 3,832 2.7G 1
pdfcpu (Go) pdfcpu 100 218M 5
Chromium PDFium (C++) PDFIUM 379 212M 5
pdfkit (JS) pdfkit 38 35M 5
pdfminer.six (Python) pdfminer.six 123 106M 5
PikePDF (Python) pikepdf 23 30M 5
Apache POI POI 11 940K 5
Poppler (C/C++) poppler 1,585 6.2G 5
Poppler (C/C++) poppler-gitlab 463 926M 6
Prawn PDF (Ruby) prawn 53 69M 5
qpdf (C++) qpdf 111 324M 5
react-pdf (JS) react-pdf 14 2.2M 5
Redhat Linux REDHAT 1,712 1.3G 5
Sumatra PDF (C/C++) sumatrapdf 320 788M 5
tabula tabula 2 172K 5
tabula-java (Java) tabula-java 77 45M 5
Apache TIKA (Java) TIKA 155 156M 2
TOTAL: 35 - 32,679 31G -

The fundamental value of the corpus comes from the ability to leverage and learn from the issues discovered by others. As a simple example; a quick test of pdfcpu (the Go-based PDF parser) resulted in 12 files timing out while being processed. An issue has been raised and already fixed:

Parsing errors screen-shot

Version 2 of the “Issue Tracker” corpus also re-crawled all the issue trackers that were in the initial release. As a result, PDF file attachments removed by their maintainers since version 1 will no longer be in the version 2 corpus downloads. The initial release of the “Issue Tracker” corpus will remain available for download at

This README file describes the overall issue tracker corpus and how data has been collated.

This README file describes the PDF-centric issue tracker corpus that is pre-packaged into six compressed tarball (.tgz files) (see The broader multi-format Issue Tracker corpus, which includes many more formats than just PDF  and is used for testing Apache Tika, is at, however these files are not pre-packaged.

As the corpus is a direct and unfiltered collation of attachment data from numerous public issue trackers, the corpus does contain a few PDF files that will trigger anti-virus/anti-malware software on various platforms. Like everything downloaded from the internet, you should always ensure good cyber-hygiene practices when handling this data.

For more information and to stay up-to-date with the “Issue Tracker” PDF corpus, please join the email list (via and, for PDF Association members, please provide your feedback or comments in the PDF TWG.

The PDF Association again wishes to thank the NASA JPL and Apache Tika teams, and particularly Dr. Tim Allison, for their efforts in maintaining the technology and collating the data. We also wish to thank Maruan Sahyoun of PDF Association member FileAffairs GmbH, part of the Apache PDFBox team, for hosting the “Issue Tracker” PDF corpus as a valuable new industry resource.


This material is based upon work supported by the Defense Advanced Research Projects Agency (DARPA) under Contract No. HR001119C0079. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Defense Advanced Research Projects Agency (DARPA). Approved for public release.



Peter Wyatt
Peter Wyatt

Peter Wyatt is the PDF Association’s CTO and an independent technology consultant with deep file format and parsing expertise. A developer and researcher working on PDF technologies for more than 20 years, he is ISO Project Leader of ISO 32000 (the core PDF standard), co-Chairs the PDF Association’s PDF TWG and is the PDF Association’s Principal Scientist leading the organization’s …


Peter Wyatt

Peter Wyatt

Peter Wyatt is the PDF Association’s CTO and an independent technology consultant with deep file format and parsing expertise. A …