CVE-2026-78207
Gravedad CVSS v4.0:
CRÍTICA
Tipo:
No Disponible / Otro tipo
Fecha de publicación:
24/08/2026
Última modificación:
24/08/2026
Descripción
*** Pendiente de traducción *** exceljs-hardened before 5.0.0 contains a prototype pollution vulnerability in the deepMerge helper that fails to reject __proto__, constructor, or prototype keys when merging note objects. Attackers can assign parsed JSON with a malicious __proto__ property to cell notes, modifying Object.prototype and affecting all plain objects created in the process.
Impacto
Puntuación base 4.0
9.30
Gravedad 4.0
CRÍTICA
Puntuación base 3.x
9.40
Gravedad 3.x
CRÍTICA
Referencias a soluciones, herramientas e información
- https://github.com/exceljs/exceljs
- https://github.com/exceljs/exceljs/blob/v4.4.0/lib/utils/under-dash.js#L155-L181
- https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-qwr4-7h29-chpf
- https://www.vulncheck.com/advisories/exceljs-through-prototype-pollution-via-deepmerge-reached-from-note-serialization


