CVE-2023-51987Public exploitNetwork attack vector

Administrator access via zero-length password comparison

Published Jan 11, 2024 · Updated Jun 20, 2025

Authentication bypass in the HNAP1 interface of D-Link DIR-822+ 1.0.2 allows remote attackers to access administrator accounts. The login handler passes the client-controlled LoginPassword length to strncmp; a null byte produces a zero-length comparison that returns equality without comparing password bytes. Network access to HNAP1 is sufficient, and successful exploitation grants administrator-level access to the router.

CVSS severity9.8
Critical
EPSS probability0.92%
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 the HNAP1 interface of D-Link DIR-822+ 1.0.2 allows remote attackers to access administrator accounts. The login handler passes the client-controlled LoginPassword length to strncmp; a null byte produces a zero-length comparison that returns equality without comparing password bytes. Network access to HNAP1 is sufficient, and successful exploitation grants administrator-level access to the router.

The record

CVE
CVE-2023-51987
Published
Jan 11, 2024
Updated
Jun 20, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-306, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 11, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 20, 2025Record 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

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS: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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1190Exploit Public-Facing Application

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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