HIGHCVSS v3.1 7.0Vulnerability
CVE-2026-128337
ExcelJS through 4.4.0 contains a prototype pollution vulnerability in mergeConditionalFormattings that allows attackers to modify Object.prototype by supplying an x14:cfRule id of __proto__. Attackers can craft an xlsx file that, when loaded with xlsx.load(), sets properties such as type, direction, border and cfvo on every object in the process until it restarts.
Properties
- Severity
- HIGH
- Nvd fetched at
- 2026-11-14T00:40:25.638091+00:00
- Epss score
- 0.00445
- Cvss severity
- HIGH
- Cvss score
- 7
- Retrieved at
- 2026-11-14T00:51:03+00:00
- Last source
- FIRST EPSS
- Score
- 7
- Cvss version
- 3.1
- Cve id
- CVE-2026-128337
- Cvss vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
- First seen by Signal
- 2026-11-13T17:31:47+00:00
- Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
- Published at
- 2026-11-13T10:18:13.920
- Last modified
- 2026-11-13T15:48:52.237
- Epss percentile
- 0.39182
Related Entities (1)
HAS_WEAKNESS (1)
Related research
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