GHSA-j2w7-387v-m2rq: Composer/phpoffice/phpspreadsheet vulnerability

Summary

When PhpSpreadsheet loads an OpenDocument Spreadsheet (.ods), Ods::processTableRow() reads the table:number-rows-repeated attribute of a <table:table-row> with an unchecked (int) cast, then materialises one cell per repeated row. This value is completely unbounded, so a single ~1.4 KB file can instruct the reader to create up to millions of cells, exhausting memory (fatal OOM). No authentication, no special configuration, and the default read filter are required - any application that loads a user-supplied .ods is affected.

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Affected versions

The number-rows-repeated expansion has existed in the ODS reader since its inception (pre-dating the current release branches), so all maintained lines are affected.

| Branch | Affected | |--------|----------| | 1.x | ≤ 1.30.6 | | 2.0–2.1 | ≤ 2.1.18 | | 2.2–2.4 | ≤ 2.4.7 | | 3.x | ≤ 3.10.7 | | 4.x–5.x | ≤ 5.9.0 (latest) |

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Root cause (source → sink)

src/PhpSpreadsheet/Reader/Ods.php:

php // line 816 — row repeat, unchecked (int) cast $rowRepeats = (int) $childNode->getAttributeNS($tableNs, 'number-rows-repeated'); ... // line 1151 — row materialisation loop: NO upper bound for ($rowAdjust = 0; $rowAdjust < $rowRepeats; ++$rowAdjust) { $rID = $rowID + $rowAdjust; $cell = $spreadsheet->getActiveSheet()->getCell($columnID . $rID); // allocates a Cell $cell->setValueExplicit($dataValue, $type); // ... no bounds check on $rowAdjust or $rID ... }

Why columns are NOT vulnerable (already bounded):

The column-header loop at line 1326 shows the correct pattern with bounds checking:

php // line 1326 (processTableColumnHeader): BOUNDED correctly for ($rowRepeats2 = $rowRepeats; $rowRepeats2 > 0 && $tableColumnIndex2 <= AddressRange::MAXCOLUMNINT; --$rowRepeats2) { // HAS BOUNDS CHECK: && $tableColumnIndex2 <= AddressRange::MAXCOLUMNINT }

Additionally, the cell-data column loop at line 1141 calls getCell() which throws exception at Coordinate.php:448 when column exceeds MAXCOLUMNINT (XFD / 16,384):

php // Coordinate.php line 448 if ($columnIndex > self::MAXCOLUMNINT) { throw new Exception('Column string index can not be beyond XFD'); }

Result: Columns are capped at 16,384. Only rows are unbounded.

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Impact

Memory exhaustion (single valued cell, repeated many rows): A non-null cell value with a huge number-rows-repeated attribute materialises millions of Cell objects → PHP fatal Allowed memory size ... exhausted.

Example: - Payload: <table:table-row table:number-rows-repeated="5000000"> (5 million rows) - File size: 1.4 KB - Memory consumed: ~256 MB (one Cell object per row) - Result: OOM at default memory limit

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Reproduction

Vulnerable payload (causes OOM):

xml <table:table table:name="Sheet1"> <table:table-row table:number-rows-repeated="5000000"> <table:table-cell office:value-type="float" office:value="1"> <text:p>1</text:p> </table:table-cell> </table:table-row> </table:table>

Not vulnerable (for reference - throws exception):

xml <table:table table:name="Sheet1"> <table:table-row> <table:table-cell office:value-type="float" office:value="1" table:number-columns-repeated="1000000000"> <text:p>1</text:p> </table:table-cell> </table:table-row> </table:table>

This column-repeat example throws Column string index can not be beyond XFD exception (bounded defense, already in place).