CVE-2026-59876

MediumCVSS 4.8/10Last modified Oct 25, 2026

Description

protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 until 8.6.5, the protobufjs Text Format extension parsed string-keyed map entries using ordinary property assignment, allowing a map entry with key __proto__ to change the prototype of the returned map object instead of creating an own map entry in protobufjs/ext/textformat. This issue is fixed in version 8.6.5.

Metrics

CVSS 3.1 4.8/10CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Weakness enumeration

Affected software

No affected versions have been published.

Timeline

Published
Jul 8, 2026
Last modified
Oct 25, 2026
NVD status
Analyzed

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CVE-2026-59876: Medium severity, CVSS 4.8 | Vulnix