What is CVE-2026-3861?

CVE-2026-3861 is a medium-severity vulnerability in Linecorp Line, classified under User Interface (UI) Misrepresentation of Critical Information. CVSS score: 6.5/10. Published 2026-04-16.

How severe is CVE-2026-3861?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Linecorp Line

CVE-2026-3861

LINE client for iOS versions prior to 26.3.0 contains a vulnerability in the in-app browser where opening a crafted web page can repeatedly trigger OS-level dialogs due to insufficient safeguards when handling arbitrary URL schemes, potentially causing the iOS device to become temporarily inoperable.

Published 2026-04-16 · last modified 2026-07-08.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (25.5th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 25.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

Linecorp Line
Ly Corporation Line Client For iOS — versions 26.3.0

Weakness classification (CWE)

CWE-451 — User Interface (UI) Misrepresentation of Critical Information

References

hackerone.com/reports/3422905 (Permissions Required)

Frequently asked questions

What is CVE-2026-3861?: CVE-2026-3861 is a medium-severity vulnerability in Linecorp Line, classified under User Interface (UI) Misrepresentation of Critical Information. CVSS score: 6.5/10. Published 2026-04-16.
How severe is CVE-2026-3861?: Medium severity. CVSS v3 base score is 6.5 out of 10.