Uninitialized string offset in Xls.php

[MatthiasKuehneEllerhold]

This is:

- [x] a bug report
- [ ] a feature request
- [x] **not** a usage question (ask them on https://stackoverflow.com/questions/tagged/phpspreadsheet or https://gitter.im/PHPOffice/PhpSpreadsheet)

What is the expected behavior?

Correct parsing of an XLS file. No errors / notices thrown. No running into the execution timeout.

What is the current behavior?

NOTICE (5): ErrorException: Uninitialized string offset: 2386 in /x/y/Logger.php:86
   1701 Stack trace:
   1702 #0 /x/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Xls.php(7886): \Logger::Log\{closure}(8, 'Uninitialized s...', '/var/...', 7886, Array)
   1703 #1 /x/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Xls.php(2981): PhpOffice\PhpSpreadsheet\Reader\Xls::getUInt2d('9\x02\x00\x009\x02\x00\x00\x12\x00\x00Plak...', 2386)
   1704 #2 /x/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Xls.php(727): PhpOffice\PhpSpreadsheet\Reader\Xls->readSst()
   1705 #3 /x/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/IOFactory.php(86): PhpOffice\PhpSpreadsheet\Reader\Xls->load('/var/www/ellerh...')
   1706 #4 /Parser.php(32): PhpOffice\PhpSpreadsheet\IOFactory::load('/var/...')

(Same happened for offset 2387.)
The read took forever and was stopped after 30 seconds because of an execution timeout.

What are the steps to reproduce?

This error occured when an XLS file was read. I cant make the spreadsheet public, because it contains business data.
This is the first spreadsheet that exhibit this behaviour, all other spreadsheets from this source were correctly read & parsed.

We've got a hold of the XLS file. The process was that a generated XLS file was edited by hand in Office 365 and saved. The original generated file could be parsed without any problem, the edited file lead to this error.
Reopening the edited file in Excel 2016 and saving it (without any modification) fixed it and the parsing worked flawlessly.

Which versions of PhpSpreadsheet and PHP are affected?

phpoffice/phpspreadsheet: 1.13.0
PHP: 7.4.8

[ggiovinazzo]

I faced a similar problem. And I managed to solve it with a fix in Xls Reader (I will submit a PR asap).

The issue is due to Bad SST Length in Xls file. I've already created a fix and I'm writing a test for this. Will reply when all is Ok to me.

[georgique]

Hey folks, any updates on this?
@ggiovinazzo I would use your fix as a temporary measure, but seems your commit has only the test. Can you tell how you've fixed the issue?

[ggiovinazzo]

@georgique that's because in my first PR I forgot to push the test.
You can see full changes in PR log https://github.com/PHPOffice/PhpSpreadsheet/pull/1623/files

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.
If this is still an issue for you, please try to help by debugging it further and sharing your results.
Thank you for your contributions.

[oleibman]

Closing. Issue was supposed to be resolved by PR #1623 in Dec. 2020. In the absence of a test file associated with this ticket, and the lack of activity since then, it seems reasonable to think that the fix was effective.