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

Date Jul 23, 2026

Type Vendor advisory

Signal High-risk advisory

Vendor / Product Composer · phpoffice/phpspreadsheet

CVE CVE-2026-59933

High-risk advisory CVE-2026-59933

Summary

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

Why it matters

GitHub has published a reviewed security advisory for phpoffice/phpspreadsheet. Prioritize it with other application dependency updates.

Operator check

Check whether phpoffice/phpspreadsheet is present in application dependency manifests, lockfiles, or build images. Review the GitHub advisory and upgrade to a patched version where available.

Sources

GitHub Advisory GHSA-xh5m-36r6-47m3 NVD — CVE-2026-59933 Source reference

PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.

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