CVE-2026-27017

Katalog CVE

CVSS 5.3 · Medium EPSS 0,19%

Kerentanan Use of a Cryptographic Primitive with a Risky Implementation pada refraction-networking utls. Skor CVSS 3.1 5.3 (Medium) menurut NVD.

Deskripsi (NVD)

uTLS is a fork of crypto/tls, created to customize ClientHello for fingerprinting resistance while still using it for the handshake. Versions 1.6.0 through 1.8.0 contain a fingerprint mismatch with Chrome when using GREASE ECH, related to cipher suite selection. When Chrome selects the preferred cipher suite in the outer ClientHello and for ECH, it does so consistently based on hardware support—for example, if it prefers AES for the outer cipher suite, it also uses AES for ECH. However, the Chrome parrot in uTLS hardcodes AES preference for outer cipher suites but selects the ECH cipher suite randomly between AES and ChaCha20. This creates a 50% chance of selecting ChaCha20 for ECH while using AES for the outer cipher suite, a combination impossible in Chrome. This issue only affects GREASE ECH; in real ECH, Chrome selects the first valid cipher suite when AES is preferred, which uTLS handles correctly. This issue has been fixed in version 1.8.1.

Rincian

Terbit di NVD

20 Februari 2026

Terakhir diubah

17 Juni 2026

Status NVD

Analyzed

CVSS 3.1

5.3 (Medium), sumber NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N · uraikan di kalkulator

Jenis kelemahan (CWE)

CWE-1240: Use of a Cryptographic Primitive with a Risky Implementation

EPSS (30 hari)

0,19% peluang dieksploitasi; lebih tinggi dari 8,2% CVE lain

Produk dan versi terdampak

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

• https://github.com/refraction-networking/utls/security/advisories/GHSA-7m29-f4hw-g2vx patch · advisory vendor