CVE-2020-26891: matrix synapse

csirt@kutim:~/threat-intel/cve/CVE-2020-26891

CVSS 6.1 · Medium EPSS 1,9%

Kerentanan Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') pada matrix synapse. Skor CVSS 3.1 6.1 (Medium) menurut NVD.

Deskripsi (NVD)

AuthRestServlet in Matrix Synapse before 1.21.0 is vulnerable to XSS due to unsafe interpolation of the session GET parameter. This allows a remote attacker to execute an XSS attack on the domain Synapse is hosted on, by supplying the victim user with a malicious URL to the /_matrix/client/r0/auth/*/fallback/web or /_matrix/client/unstable/auth/*/fallback/web Synapse endpoints.

Rincian

Terbit di NVD: 19 Oktober 2020
Terakhir diubah: 17 Juni 2026
Status NVD: Modified
CVSS 3.1: 6.1 (Medium), sumber NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N · uraikan di kalkulator
Jenis kelemahan (CWE): CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
EPSS (30 hari): 1,9% peluang dieksploitasi; lebih tinggi dari 79,4% CVE lain

Produk dan versi terdampak

Vendor	Produk	Versi terdampak
matrix	synapse	Semua versi sebelum 1.21.0

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory release notes · advisory vendor
https://github.com/matrix-org/synapse/pull/8444 issue tracking · patch · advisory pihak ketiga
https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq patch · advisory pihak ketiga
https://github.com/matrix-org/synapse/releases/tag/v1.21.2 release notes · advisory pihak ketiga

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.