CVE-2023-40039

Wireless access via beacon-derived default key

Published Sep 11, 2023 · Updated Sep 26, 2024

Default credential weakness in ARRIS TG852G, TG862G, and TG1672G gateways allows remote attackers to derive the WPA2-PSK from a beacon frame. The default-key generation scheme makes the factory PSK reproducible from beacon data, although the published record omits the exact derivation formula. The attack requires Wi-Fi proximity and an unchanged default key; recovering that key permits unauthorized wireless-network access.

CVSS severity9.8
Critical
EPSS probability1.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Default credential weakness in ARRIS TG852G, TG862G, and TG1672G gateways allows remote attackers to derive the WPA2-PSK from a beacon frame. The default-key generation scheme makes the factory PSK reproducible from beacon data, although the published record omits the exact derivation formula. The attack requires Wi-Fi proximity and an unchanged default key; recovering that key permits unauthorized wireless-network access.

The record

CVE
CVE-2023-40039
Published
Sep 11, 2023
Updated
Sep 26, 2024
Vendor
ARRIS
Product
TG852G
Classifications
CWE-284, T1040
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 26, 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?

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  1. Affected versionversion=tg852g

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

ARRIS · TG852Gversion=tg852g
ARRIS · TG1672Gversion=tg1672g
ARRIS · TG862Gversion=tg862g

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1040Network Sniffing

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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