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  4. CVE 2026 109434 sleipnir browser 390 fullscreen address bar
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Back to active CVEs
Medium · CVSS 5.1CVE-2026-109434

Sleipnir Browser < 3.9.0 Fullscreen Address Bar SpoofingCVE-2026-109434

Answer in brief

CVE-2026-109434 records a Medium severity (CVSS 5.1) vulnerability in Sleipnir Browser < 3.9.0 Fullscreen Address Bar Spoofing. The current sources do not mark it as known exploited. The current feed maps Fenrir/Sleipnir Mobile for Android (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 19, 2026Updated Oct 19, 2026Source checked Oct 19, 2026First seen by HOL Oct 19, 2026Material review Oct 19, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 5.1
Exploitation
Not marked as known exploited
Affected software
1 mapped package or product
Fix availability
Available

Why this deserves its current priority

CVSS is 5.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Fenrir/Sleipnir Mobile for Android (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Fenrir/Sleipnir Mobile for Androidgeneric>=0 <3.9.03.9.0

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Fenrir/Sleipnir Mobile for Android.
  2. 2Review the reported fix. Update Fenrir/Sleipnir Mobile for Android to 3.9.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Oct 19, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 19, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Oct 19, 2026

Sources and claim methodology

  • Source referencefenrir-inc.com
  • Source referencevulncheck.com
Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.

Record context

Vulnerability class
Secret Exfiltration
EPSS
Not reported
CWE IDs
CWE-451
Source
CVE List V5
Source checked
Oct 19, 2026
References
2 linked sources
Open source record