Vulnerability in Rakuten Viber
CVE-2025-13476
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)
Vulnerability class: POODLE (CVE-2014-3566)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.003 (25.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Rakuten Viber — versions 9.3.0.6
- Rakuten Viber Cloak - Android — versions 25.7.2.0g
- Rakuten Viber Cloak - Windows — versions v25.6.0.0
Weakness classification (CWE)
References
- www.viber.com/en/download/ (Product)
- af854a3a-2127-422b-91ae-364da2661108 (Third Party Advisory)
Frequently asked questions
- What is CVE-2025-13476?
- CVE-2025-13476 is a critical-severity vulnerability in Rakuten Viber, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 9.8/10. Published 2026-03-05.
- How severe is CVE-2025-13476?
- Critical severity. CVSS v3 base score is 9.8 out of 10.