In-App Browser Vulnerability in LINE Client for iOS
CVE-2026-3861

6.5MEDIUM

Key Information:

Vendor: Line Corporation
Status: Line Client For iOS
Vendor: CVE Published:; 16 April 2026

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What is CVE-2026-3861?

The LINE client for iOS, prior to version 26.3.0, has a significant flaw in its in-app browser that allows specially crafted web pages to trigger repetitive OS-level dialog prompts. This behavior can lead to the iOS device becoming temporarily inoperable, causing user frustration and potential workflow interruptions. Users of affected versions should upgrade to the latest version to mitigate this issue.

Affected Version(s)

LINE client for iOS - < 26.3.0

References

https://hackerone.com/reports/3422905

CVSS V3.1

Score:

6.5

Severity:

MEDIUM

Confidentiality:

None

Integrity:

None

Availability:

None

Attack Vector:

Network

Attack Complexity:

Low

Privileges Required:

None

User Interaction:

Required

Scope:

Unchanged

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Timeline

Vulnerability published
Apr 16, 2026
Vulnerability Reserved
Mar 10, 2026

CVE-2026-3861 Data

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