CVE-2021-36214Public exploitNetwork attack vector

Cross-site scripting via octet-stream WebView rendering

Published Jul 13, 2021 · Updated Apr 9, 2026

Cross-site scripting in LINE client for iOS before 10.16.3 allows remote attackers to execute script through a crafted WebView response. The WebView renders a response labeled application/octet-stream as HTML instead of treating it as a download, allowing embedded markup and script to run. Exploitation requires a user to open attacker-controlled content; executed script can read or alter data available to the rendered page.

CVSS severity6.1
Medium
EPSS probability0.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in LINE client for iOS before 10.16.3 allows remote attackers to execute script through a crafted WebView response. The WebView renders a response labeled application/octet-stream as HTML instead of treating it as a download, allowing embedded markup and script to run. Exploitation requires a user to open attacker-controlled content; executed script can read or alter data available to the rendered page.

The record

CVE
CVE-2021-36214
Published
Jul 13, 2021
Updated
Apr 9, 2026
Vendor
LINE Corporation
Product
LINE
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< <10.16.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LINE Corporation · LINEversion=< <10.16.3

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1LINE CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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