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.

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 b…

Vulnerability class: POODLE (CVE-2014-3566)

EPSS: 0.003 (26.3th percentile) — read the EPSS interpretation.

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.

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)

CWE-327 — Use of a Broken or Risky Cryptographic Algorithm

References

cret@cert.org (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.