CVE-2025-13476

Severity CVSS v4.0:

Pending analysis

Type:

CWE-327 Use of a Broken or Risky Cryptographic Algorithm

Publication date:

05/03/2026

Last modified:

10/03/2026

Description

Rakuten Viber Cloak mode in Android v25.7.2.0g and Windows v25.6.0.0–v25.8.1.0 uses a static and predictable TLS ClientHello fingerprint lacking extension diversity, allowing Deep Packet Inspection (DPI) systems to trivially identify and block proxy traffic, undermining censorship circumvention. (CWE-327)

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 9.80 CRITICAL
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x

9.80

Severity 3.x

CRITICAL

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:rakuten:viber::::::windows::*	25.6.0 (including)	25.8.1.0 (including)
cpe:2.3:a:rakuten:viber:9.3.0.6:25.7.2.0g::::android::*

To consult the complete list of CPE names with products and versions, see this page

CVE-2025-13476

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools