CVE-2023-39731Network attack vector

Broadcast-message spoofing via leaked client secret

Published Oct 19, 2023 · Updated Sep 13, 2024

Client-secret exposure in LINE Kaibutsunosato 13.6.1 allows remote attackers to obtain a channel access token over the network. Published sources do not identify the page, request, or storage location that exposes the client secret, only that it is leaked. No authentication or user interaction is required; possession of the derived channel access token permits crafted broadcast messages to be sent as the affected channel.

CVSS severity5.3
Medium
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Client-secret exposure in LINE Kaibutsunosato 13.6.1 allows remote attackers to obtain a channel access token over the network. Published sources do not identify the page, request, or storage location that exposes the client secret, only that it is leaked. No authentication or user interaction is required; possession of the derived channel access token permits crafted broadcast messages to be sent as the affected channel.

The record

CVE
CVE-2023-39731
Published
Oct 19, 2023
Updated
Sep 13, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-284, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 19, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 13, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1528Steal Application Access Token

Public exploit references

No public exploit references are available in this record.

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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