PhpSpreadsheet: XLS/OLE sector-chain self-loop causes memory exhaustion

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-59933
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-28 18:17:23 UTC
Updated2026-07-28 19:17:39 UTC
DescriptionPhpSpreadsheet 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA PHPOffice PhpSpreadsheet affected >= 4.0.0, < 5.8.1 Not specified
CNA PHPOffice PhpSpreadsheet affected >= 3.3.0, < 3.10.7 Not specified
CNA PHPOffice PhpSpreadsheet affected >= 2.2.0, < 2.4.7 Not specified
CNA PHPOffice PhpSpreadsheet affected >= 2.0.0, < 2.1.18 Not specified
CNA PHPOffice PhpSpreadsheet affected < 1.30.6 Not specified

References

ReferenceSourceLinkTags
github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-xh5m-36r6-47m3 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/PHPOffice/PhpSpreadsheet/releases/tag/2.1.18 [email protected] github.com
github.com/PHPOffice/PhpSpreadsheet/commit/85f2556b0bf5269061bf45932ecda... [email protected] github.com
github.com/PHPOffice/PhpSpreadsheet/releases/tag/1.30.6 [email protected] github.com
github.com/PHPOffice/PhpSpreadsheet/releases/tag/5.8.1 [email protected] github.com
github.com/PHPOffice/PhpSpreadsheet/releases/tag/2.4.7 [email protected] github.com
github.com/PHPOffice/PhpSpreadsheet/releases/tag/3.10.7 [email protected] github.com
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