CVE-2026-109434

Sleipnir Browser < 3.9.0 Fullscreen Address Bar Spoofing

CVSS score

5.1

EPSS probability

—

Risk score

0.5

Published

4 h ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

Impact on My Inventory

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Vulnerability description

CVE AI research

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DayBreach AI Explanation

Verified against sources

Sleipnir Browser UI Spoofing Vulnerability

Sources read

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

CVE-2026-109434 affects Fenrir Sleipnir Browser for Android, allowing the use of fullscreen mode without a persistent notification or trusted-origin indicator. This enables remote attackers to impersonate the trusted address bar and present counterfeit interfaces.

Why does it matter?

This vulnerability can lead users to expose their credentials or encounter malware through fake login or payment pages.

What should be done?

Apply updates by following vendor advisories [S0].

Chain of evidence and sources2 verified claims

Sleipnir Browser for Android 3.9.0 öncesi sürümlerde arayüz aldatmacası zaafiyeti bulunmaktadır.

S0 · daybreach-canonical S1 · cvelist

Saldırganlar tam ekran API'sini kullanarak sahte bir adres çubuğu oluşturabilir.

S0 · daybreach-canonical S1 · cvelist

Show the technical text from the sources

Fenrir Sleipnir Browser for Android before 3.9.0 contains a UI spoofing vulnerability that allows remote attackers to impersonate the browser's trusted address bar by entering fullscreen mode via the Fullscreen API without displaying a persistent notification or trusted-origin indicator. Attackers can render a counterfeit address bar showing a trusted origin over attacker-controlled content after a single user tap, enabling credential harvesting, malware delivery, or social engineering through fake login, update, or payment pages.

CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CWE: CWE-451

Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-109434 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	Fenrir	Sleipnir Mobile for Android	View

Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
5.1	CVSS V4_0	MEDIUM	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N	CVE CNA
5.1	CVSS V40	MEDIUM	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD
4.3	CVSS V3_1	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N	CVE CNA
4.3	CVSS V31	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N	NVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

cvelist

Vendor Advisory

Open source

reference

Vendor Advisory

Open source

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Apply the official update named in the evidence only to the matching product and version.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-109434 is associated with the following CWEs:

CWE-451: Common Weakness Enumeration Entry CWE-451

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-109434 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

User—

Official Sources and Advisories

Vendor Advisorypatch VulnCheck Advisory: Sleipnir Browser < 3.9.0 Fullscreen Address Bar Spoofingvendor-advisory

CVSS Vector Radar Chart

5.1 / 10

Vulnerability Scoring Details

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User InteractionA

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)A

Availability (Erişilebilirlik)None

Yama doğrulandı

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

Fenrir

Weakness Type (CWE & CAPEC)

CWE-451

Get this vulnerability through the API

Affected products, version ranges, exploitation status and patch information in a single request, with a free key.

Get a free key Documentation

curl -H "x-api-key: $DAYBREACH_API_KEY" \
  "https://api.daybreach.dev/api/v1/intel/cves/CVE-2026-109434"