CVE-2026-59933

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.

Affected Software

VendorProductVersion RangeStatus
PHPOfficePhpSpreadsheet>= 4.0.0, < 5.8.1affected
PHPOfficePhpSpreadsheet>= 3.3.0, < 3.10.7affected
PHPOfficePhpSpreadsheet>= 2.2.0, < 2.4.7affected
PHPOfficePhpSpreadsheet>= 2.0.0, < 2.1.18affected
PHPOfficePhpSpreadsheet< 1.30.6affected

Weaknesses

  • CWE-400: CWE-400: Uncontrolled Resource Consumption
  • CWE-835: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

Additional References

References