VulnerabilityPublished 24 Jan 2024Updated 30 May 2025

CVE-2023-43990

Source CVE Database V5

Not known to be exploited · CVSS 5.4 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

5.4Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Jan 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

To mitigate this vulnerability, European organizations should prioritize the following actions: 1) Monitor for updates and patches from Line or the mini-app developers and apply them promptly once available. 2) Restrict and monitor access to channel access tokens, ensuring they are stored securely and rotated regularly to minimize the risk of leakage. 3) Implement network-level controls to detect and block suspicious notification traffic that deviates from normal patterns. 4) Educate users about the risks of malicious notifications and encourage verification of unexpected or unusual messages, even if they appear to come from trusted sources. 5) Employ multi-factor authentication and additional verification steps for sensitive actions initiated via the Line app to reduce the impact of token compromise. 6) Conduct regular security assessments of any integrated mini-apps or third-party components within communication platforms to identify and remediate vulnerabilities proactively.

Description

An issue in cherub-hair mini-app on Line v13.6.1 allows attackers to send crafted malicious notifications via leakage of the channel access token.

Impact

For European organizations, the impact of this vulnerability could be significant, especially for those relying on Line for internal or external communications, customer engagement, or marketing. Malicious notifications could lead to targeted phishing campaigns, resulting in credential theft, unauthorized access to corporate resources, or the spread of disinformation that undermines trust and operational integrity. Organizations in sectors such as finance, healthcare, and government could be particularly vulnerable due to the sensitivity of their communications and the potential regulatory implications of data breaches or misinformation. Additionally, the compromise of channel access tokens could allow attackers to impersonate legitimate communication channels, damaging brand reputation and causing financial loss. Given the network-based attack vector and the lack of required user interaction, the threat could propagate rapidly if exploited, increasing the risk of widespread impact within organizations that have integrated Line into their communication workflows.

References

github.com/syz913/CVE-reports/blob/main/CVE-2023-43990.md (opens in a new tab)

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 8 Jul 2025, 19:25 UTC

Technical details

References

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