CVE-2025-13476 Rakuten Viber uses broken or risky cryptographic Algorithm

What is CVE-2025-13476?

CVE-2025-13476 is a critical vulnerability in Rakuten Viber Cloak - Android, published on 5 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

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)

Weakness: CWE-327

Which versions are affected by CVE-2025-13476?

It affects 1 product.

Products include Rakuten Viber.

How do I fix CVE-2025-13476?

No fix has been published for CVE-2025-13476 yet. Limit exposure of the affected software until one is available.

Is CVE-2025-13476 being exploited?

There is no known exploitation of CVE-2025-13476 in the wild and no public exploit code.

Other vulnerabilities in Rakuten Viber Cloak - Android

• CVE-2019-18800 Information disclosure in n/a High 8.8
• CVE-2019-12569 Path traversal in n/a High 7.8
• CVE-2020-14049 Other in n/a High 7.5
• CVE-2025-55996 Cross-site scripting in n/a Medium 6.3
• CVE-2018-3987 Information disclosure in Rakuten Viber Medium 4.2

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-7qg4-wvfj-q8vh.