Vulnerability · Published Mar 5, 2026 · Assigned by certcc
CVE-2025-13476Rakuten Viber uses broken or risky cryptographic Algorithm
Critical 9.8
In plain English
A critical-severity security flaw in Rakuten Viber Cloak - Android from Rakuten Viber. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.4%top 69.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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)
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Rakuten Viber | Rakuten Viber Cloak - Android | 25.7.2.0g – before 27.2.0.0g |
| Rakuten Viber | Rakuten Viber Cloak - Windows | v25.6.0.0 – before v27.3.0.0 |