PhpSpreadsheet: XLS/OLE sector-chain self-loop causes memory exhaustion
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-400.
Summary
PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. In versions 4.0.0 through 5.8.0, 3.3.0 through 3.10.6, 2.2.0 through 2.4.6, 2.0.0 through 2.1.17, and all releases up to and including 1.30.5, the OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed .xls/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, OLERead::read() appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from Reader\Xls::canRead() and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. This issue has been fixed in versions 5.8.1, 3.10.7, 2.4.7, 2.1.18 and 1.30.6.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| PHPOffice | PhpSpreadsheet | 4.0.0 to before 5.8.1; 3.3.0 to before 3.10.7; 2.2.0 to before 2.4.7; 2.0.0 to before 2.1.18; before 1.30.6 | 5.8.1, 3.10.7, 2.4.7, 2.1.18, 1.30.6 | Patch available | CNA |
| — | phpoffice/phpspreadsheet (Packagist) | 4.0.0 to before 5.8.1 | 5.8.1 | Patch available | GHSA-xh5m-36r6-47m3 |
| — | phpoffice/phpspreadsheet (Packagist) | 3.3.0 to before 3.10.7 | 3.10.7 | Patch available | GHSA-xh5m-36r6-47m3 |
| — | phpoffice/phpspreadsheet (Packagist) | 2.2.0 to before 2.4.7 | 2.4.7 | Patch available | GHSA-xh5m-36r6-47m3 |
| — | phpoffice/phpspreadsheet (Packagist) | 2.0.0 to before 2.1.18 | 2.1.18 | Patch available | GHSA-xh5m-36r6-47m3 |
| — | phpoffice/phpspreadsheet (Packagist) | before 1.30.6 | 1.30.6 | Patch available | GHSA-xh5m-36r6-47m3 |
- PhpSpreadsheet VendorPHPOffice Affected 4.0.0 to before 5.8.1; 3.3.0 to before 3.10.7; 2.2.0 to before 2.4.7; 2.0.0 to before 2.1.18; before 1.30.6 Fixed in 5.8.1, 3.10.7, 2.4.7, 2.1.18, 1.30.6 Patch available CNA
- phpoffice/phpspreadsheet (Packagist) Vendor— Affected 4.0.0 to before 5.8.1 Fixed in 5.8.1 Patch available GHSA-xh5m-36r6-47m3
- phpoffice/phpspreadsheet (Packagist) Vendor— Affected 3.3.0 to before 3.10.7 Fixed in 3.10.7 Patch available GHSA-xh5m-36r6-47m3
- phpoffice/phpspreadsheet (Packagist) Vendor— Affected 2.2.0 to before 2.4.7 Fixed in 2.4.7 Patch available GHSA-xh5m-36r6-47m3
- phpoffice/phpspreadsheet (Packagist) Vendor— Affected 2.0.0 to before 2.1.18 Fixed in 2.1.18 Patch available GHSA-xh5m-36r6-47m3
- phpoffice/phpspreadsheet (Packagist) Vendor— Affected before 1.30.6 Fixed in 1.30.6 Patch available GHSA-xh5m-36r6-47m3
Remediation
- Fix · CNA PhpSpreadsheet (PHPOffice) Fixed in 5.8.1, 3.10.7, 2.4.7, 2.1.18, 1.30.6
- Fix · GHSA-xh5m-36r6-47m3 phpoffice/phpspreadsheet (Packagist) Fixed in 5.8.1 Advisory →
- Fix · GHSA-xh5m-36r6-47m3 phpoffice/phpspreadsheet (Packagist) Fixed in 3.10.7 Advisory →
- Fix · GHSA-xh5m-36r6-47m3 phpoffice/phpspreadsheet (Packagist) Fixed in 2.4.7 Advisory →
- Fix · GHSA-xh5m-36r6-47m3 phpoffice/phpspreadsheet (Packagist) Fixed in 2.1.18 Advisory →
- Fix · GHSA-xh5m-36r6-47m3 phpoffice/phpspreadsheet (Packagist) Fixed in 1.30.6 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-59933
- 2026-10-03 Alias added: GHSA-xh5m-36r6-47m3
- 2026-10-25 EPSS moved to the below the 50th percentile
References
Other 8
- https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-xh5m-36r6-47m3
- https://github.com/PHPOffice/PhpSpreadsheet/commit/85f2556b0bf5269061bf45932ecda8a128d81750
- https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/1.30.6
- https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/2.1.18
- https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/2.4.7
- https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/3.10.7
- https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/5.8.1
- https://github.com/PHPOffice/PhpSpreadsheet
More PHPOffice vulnerabilities
- TI-2026-32885 PhpSpreadsheet: File::prohibitWrappers bypass CVSS 4.0CRITICAL 9.2
- TI-2026-26406 PhpSpreadsheet SSRF and RCE via PHP stream wrappers in IOFactory::load CVSS 4.0CRITICAL 9.2
- TI-2026-79412 PhpSpreadsheet ODS reader exhausts CPU and memory via repeated rows CVSS 4.0HIGH 8.7
- TI-2025-34182 PhpSpreadsheet vulnerable to SSRF when reading and displaying a processed HTML document in the browser CVSS 4.0HIGH 8.7
- TI-2026-78784 Insecure deserialization in PHPOffice PHPPresentation allows code execution CVSS 4.0CRITICAL 9.2
- TI-2024-37339 PhpSpreadsheet vulnerable to unauthorized reflected XSS in Currency.php file CVSS 4.0HIGH 8.3
Sources
- CVE-2026-59933 · CVE Program
- CVE-2026-59933 · NVD
- FIRST EPSS
- GHSA-xh5m-36r6-47m3 · GitHub Advisory Database · CC BY 4.0
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