CVE-2023-39373

Authentication bypass via captured-message replay

Published Sep 3, 2023 · Updated Sep 27, 2024

Authentication bypass in Hyundai model (2017) allows attackers to replay captured traffic and assume an authenticated state. The public record identifies capture-replay but does not disclose the protocol, message, receiver, or missing freshness check involved. Exploitation requires adjacent-network access and a previously captured valid exchange; the concrete vehicle action and resulting operational effect are undisclosed.

CVSS severity6.5
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Hyundai model (2017) allows attackers to replay captured traffic and assume an authenticated state. The public record identifies capture-replay but does not disclose the protocol, message, receiver, or missing freshness check involved. Exploitation requires adjacent-network access and a previously captured valid exchange; the concrete vehicle action and resulting operational effect are undisclosed.

The record

CVE
CVE-2023-39373
Published
Sep 3, 2023
Updated
Sep 27, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-294, CAPEC-60
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 3, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 27, 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 vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5NIST National Vulnerability DatabaseCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7.4Israel National Cyber DirectorateCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
CAPEC-60Reusing Session IDs (aka Session Replay)

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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