{"id":"CVE-2026-128340","aliases":["GHSA-qvh4-wwpm-ggc8"],"url":"https://o3.security/vulnerability/CVE-2026-128340","summary":"ExcelJS through 4.4.0 Memory Exhaustion via Oversized Defined Name Range","details":"ExcelJS through 4.4.0 contains a memory exhaustion vulnerability that allows attackers to crash applications by supplying a workbook with an oversized defined-name range. DefinedNames.addEx expands ranges such as S!$A$1:$XFD$1048576 from xl/workbook.xml cell by cell, causing an uncatchable fatal heap out-of-memory error during xlsx.load().","published":"2026-11-13T09:33:35.713Z","modified":"2026-11-14T02:47:33.922635719Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/128xxx/CVE-2026-128340.json"},{"type":"PACKAGE","url":"https://github.com/exceljs/exceljs"},{"type":"ARTICLE","url":"https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/defined-names.js#L182-L193"},{"type":"ARTICLE","url":"https://github.com/exceljs/exceljs/blob/v4.4.0/lib/utils/cell-matrix.js#L28-L37"},{"type":"ADVISORY","url":"https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-qvh4-wwpm-ggc8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-128340"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/exceljs-through-4.4.0-memory-exhaustion-via-oversized-defined-name-range"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-11-14T02:47:33.922635719Z"}}