CVE-2025-13476
Rakuten Viber uses broken or risky cryptographic Algorithm
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)
INFO
Published Date :
March 5, 2026, 7:15 p.m.
Last Modified :
March 10, 2026, 7:49 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update Rakuten Viber on Android to the latest version.
- Update Rakuten Viber on Windows to the latest version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-13476.
| URL | Resource |
|---|---|
| https://www.viber.com/en/download/ | Product |
| https://www.kb.cert.org/vuls/id/772695 | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-13476 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-13476
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-13476 vulnerability anywhere in the article.
-
Daily CyberSecurity
Exposed in Plain Sight: Critical Privacy Flaw Defeats Viber’s Anti-Censorship ‘Cloak’ Mode
The CERT Coordination Center (CERT/CC) has issued a vulnerability note regarding a significant privacy flaw in Rakuten Viber, one of the world’s most popular messaging and VoIP applications. The vulne ... Read more
The following table lists the changes that have been made to the
CVE-2025-13476 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 10, 2026
Action Type Old Value New Value Added CWE CWE-327 Added CPE Configuration OR *cpe:2.3:a:rakuten:viber:*:*:*:*:*:windows:*:* versions from (including) 25.6.0 up to (including) 25.8.1.0 *cpe:2.3:a:rakuten:viber:9.3.0.6:25.7.2.0g:*:*:*:android:*:* Added Reference Type CVE: https://www.kb.cert.org/vuls/id/772695 Types: Third Party Advisory Added Reference Type CERT/CC: https://www.viber.com/en/download/ Types: Product -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Mar. 06, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by [email protected]
Mar. 05, 2026
Action Type Old Value New Value Added 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) Added Reference https://www.viber.com/en/download/ -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Mar. 05, 2026
Action Type Old Value New Value Added Reference https://www.kb.cert.org/vuls/id/772695