csirt@kutim:~/threat-intel/cve/CVE-2026-56812

Katalog CVE

CVSS 7.5 · High EPSS 0,80%

Kerentanan Improper Check for Unusual or Exceptional Conditions pada phoenixframework phoenix. Skor CVSS 3.1 7.5 (High) menurut NVD.

Deskripsi (NVD)

Improper Check for Unusual or Exceptional Conditions vulnerability in phoenixframework phoenix (Presence JavaScript client) allows an attacker with ordinary channel access to cause a persistent client-side denial of service against every viewer of a presence channel topic. This vulnerability is associated with program files assets/js/phoenix/presence.js and program routines Presence.syncState and Presence.syncDiff. The Phoenix JavaScript presence client checks whether a presence already exists with a bare truthiness test (state[key]) instead of an own-property check. Presence keys can be attacker-controlled, because applications track presences under a username or id supplied by the client. A user who joins a channel choosing a key that is an Object.prototype member name (__proto__, constructor, toString, hasOwnProperty, and similar) makes that lookup return JavaScript's built-in Object.prototype instead of undefined. Because the prototype is truthy, the code treats it as an existing presence and reads .metas.map(...) off it, which throws an uncaught TypeError. The exception propagates out of the presence message handler, so the local state is never updated and onSync() never fires. Because the malicious key is tracked on the server, it is re-pushed on every presence update and keeps re-throwing, so presence sync stays broken for every viewer of that channel topic until the attacker leaves. Both syncState and syncDiff use the same unsafe existence-check pattern. The impact is limited to the affected topic and is a read-time confusion of the prototype object, not a mutation of Object.prototype (it is not prototype pollution). This issue affects phoenix: from 1.2.0-rc.0 before 1.5.15, from 1.6.0-rc.0 before 1.6.17, from 1.7.0-rc.0 before 1.7.24, and from 1.8.0-rc.0 before 1.8.9; phoenix: from 1.2.0-rc.0 before 1.5.15, from 1.6.0-rc.0 before 1.6.17, from 1.7.0-rc.0 before 1.7.24, and from 1.8.0-rc.0 before 1.8.9.

Rincian

Terbit di NVD
7 Juli 2026
Terakhir diubah
24 September 2026
Status NVD
Modified
CVSS 3.1
7.5 (High), sumber NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H · uraikan di kalkulator
Jenis kelemahan (CWE)
CWE-754: Improper Check for Unusual or Exceptional Conditions
EPSS (30 hari)
0,80% peluang dieksploitasi; lebih tinggi dari 55,3% CVE lain

Produk dan versi terdampak

VendorProdukVersi terdampak
phoenixframework phoenix Versi 1.2.0 hingga sebelum 1.5.15
phoenixframework phoenix Versi 1.6.0 hingga sebelum 1.6.17
phoenixframework phoenix Versi 1.7.0 hingga sebelum 1.7.24
phoenixframework phoenix Versi 1.8.0 hingga sebelum 1.8.9

> 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, 20:11 WITA. Kalau sistem di Perangkat Daerah memakai produk ini dan butuh bantuan, laporkan lewat kanal pelaporan.