PhpSpreadsheet: XmlScanner Bypass via Double-Encoded unentity() TOCTOU Allows XXE and Denial of Service
High-risk advisory
CVE-2026-108357
Summary
PhpSpreadsheet: XmlScanner Bypass via Double-Encoded unentity() TOCTOU Allows XXE and Denial of Service
Why it matters
GitHub has published a reviewed security advisory for phpoffice/phpspreadsheet. Prioritize it with other application dependency updates, especially because EPSS places it in the 29% percentile.
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. CVSS score: 8.8. EPSS probability: 0.4%; percentile: 29%.
Sources
PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.