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)
CVE-2025-13476
CRITICALPre-NVD 9.89.8—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-03-05. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.8; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, ghsa
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.8
- EG Score
- 9.8(medium)
- EG Risk
- 49(Track)EG Risk 49/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity98% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 27%
- KEV
- Not listed
Published
March 5, 2026
Last Modified
June 17, 2026
Advisory Details (2)
Auto-updated Jul 27, 2026No patch confirmed yet. Sources: cert.
cert
VU#772695 - A flawed TLS handshake implementation affects Viber Proxy in multiple platforms
https://www.kb.cert.org/vuls/id/772695Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-27 14:12 UTCEPSS rescore
- 2026-07-27 13:51 UTCEG score recompute
- 2026-07-27 13:51 UTCGHSA enrichment
Frequently asked(5)
What is CVE-2025-13476?
CVE-2025-13476 is a critical vulnerability published on March 5, 2026. 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.…
When was CVE-2025-13476 disclosed?
CVE-2025-13476 was first published in the National Vulnerability Database on March 5, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-13476 actively exploited?
CVE-2025-13476 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 73.0% of all scored CVEs.
What is the CVSS score of CVE-2025-13476?
CVE-2025-13476 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2025-13476?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-13476, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2025-13476
Is Your Infrastructure Affected by CVE-2025-13476?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.