CVEvulnerability

CVE-2026-78207

9.3 CRITICAL Published 2026-08-24 Modified 2026-10-14 Official page ↗
Status
Deferred
Published
2026-08-24
Last modified
2026-10-14
Assigner
[email protected]
CVSS 4.0 ([email protected])
9.3 CRITICAL — CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
9.4 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
Weaknesses
CWE-1321

Description

exceljs through 4.4.0 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.

Related

Weakness · CWE (1)

  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes weakness

References