CVE-2021-20230: stunnel

csirt@kutim:~/threat-intel/cve/CVE-2021-20230

CVSS 7.5 · High EPSS 1,2%

Kerentanan Improper Certificate Validation pada stunnel. Skor CVSS 3.1 7.5 (High) menurut NVD.

Deskripsi (NVD)

A flaw was found in stunnel before 5.57, where it improperly validates client certificates when it is configured to use both redirect and verifyChain options. This flaw allows an attacker with a certificate signed by a Certificate Authority, which is not the one accepted by the stunnel server, to access the tunneled service instead of being redirected to the address specified in the redirect option. The highest threat from this vulnerability is to confidentiality.

Rincian

Terbit di NVD: 23 Februari 2021
Terakhir diubah: 17 Juni 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:H/I:N/A:N · uraikan di kalkulator
Jenis kelemahan (CWE): CWE-295: Improper Certificate Validation
EPSS (30 hari): 1,2% peluang dieksploitasi; lebih tinggi dari 66,8% CVE lain

Produk dan versi terdampak

Vendor	Produk	Versi terdampak
stunnel	stunnel	Semua versi sebelum 5.57

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

https://github.com/mtrojnar/stunnel/commit/ebad9ddc4efb2635f37174c9d800d06206f1edf9 patch · advisory pihak ketiga
https://bugzilla.redhat.com/show_bug.cgi?id=1925226 issue tracking · advisory pihak ketiga
https://security.gentoo.org/glsa/202105-02 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.