csirt@kutim:~/threat-intel/cve/CVE-2021-21368

Katalog CVE

CVSS 8.8 · High EPSS 1,6%

Kerentanan Improperly Controlled Modification of Dynamically-Determined Object Attributes pada msgpack5 project msgpack5. Skor CVSS 3.1 8.8 (High) menurut NVD.

Deskripsi (NVD)

msgpack5 is a msgpack v5 implementation for node.js and the browser. In msgpack5 before versions 3.6.1, 4.5.1, and 5.2.1 there is a "Prototype Poisoning" vulnerability. When msgpack5 decodes a map containing a key "__proto__", it assigns the decoded value to __proto__. Object.prototype.__proto__ is an accessor property for the receiver's prototype. If the value corresponding to the key __proto__ decodes to an object or null, msgpack5 sets the decoded object's prototype to that value. An attacker who can submit crafted MessagePack data to a service can use this to produce values that appear to be of other types; may have unexpected prototype properties and methods (for example length, numeric properties, and push et al if __proto__'s value decodes to an Array); and/or may throw unexpected exceptions when used (for example if the __proto__ value decodes to a Map or Date). Other unexpected behavior might be produced for other types. There is no effect on the global prototype. This "prototype poisoning" is sort of a very limited inversion of a prototype pollution attack. Only the decoded value's prototype is affected, and it can only be set to msgpack5 values (though if the victim makes use of custom codecs, anything could be a msgpack5 value). We have not found a way to escalate this to true prototype pollution (absent other bugs in the consumer's code). This has been fixed in msgpack5 version 3.6.1, 4.5.1, and 5.2.1. See the referenced GitHub Security Advisory for an example and more details.

Rincian

Terbit di NVD
12 Maret 2021
Terakhir diubah
17 Juni 2026
Status NVD
Modified
CVSS 3.1
8.8 (High), sumber NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H · uraikan di kalkulator
Jenis kelemahan (CWE)
CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes
CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
EPSS (30 hari)
1,6% peluang dieksploitasi; lebih tinggi dari 75,8% CVE lain

Produk dan versi terdampak

VendorProdukVersi terdampak
msgpack5 project msgpack5 Semua versi sebelum 3.6.1
msgpack5 project msgpack5 Versi 4.0.0 hingga sebelum 4.5.1
msgpack5 project msgpack5 Versi 5.0.0 hingga sebelum 5.2.1

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

Sumber: NVD · CVE.org · EPSS. Halaman ini disusun otomatis dari data tersebut; pembaruan terakhir 5 Okt 2026, 20:10 WITA. Kalau sistem di Perangkat Daerah memakai produk ini dan butuh bantuan, laporkan lewat kanal pelaporan.