CVE-2025-5623Public exploitNetwork attack vector

Unauthenticated code execution via unchecked QoS parameters

Published Jun 5, 2025 · Updated Jun 5, 2025

Stack-based buffer overflow in D-Link DIR-816 1.10CNB05 allows remote attackers to execute code through a crafted QoS request. The qosClassifier function copies oversized dip_address or sip_address values into a stack-local buffer without length validation, overwriting its return address. The web handler is reachable without authentication; the published proof of concept crashes the router, while return-address control enables arbitrary code execution.

CVSS severity9.3
Critical
EPSS probability18.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in D-Link DIR-816 1.10CNB05 allows remote attackers to execute code through a crafted QoS request. The qosClassifier function copies oversized dip_address or sip_address values into a stack-local buffer without length validation, overwriting its return address. The web handler is reachable without authentication; the published proof of concept crashes the router, while return-address control enables arbitrary code execution.

The record

CVE
CVE-2025-5623
Published
Jun 5, 2025
Updated
Jun 5, 2025
Vendor
D-Link
Product
DIR-816
Classifications
CWE-119, CWE-121, CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 5, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.10CNB05

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

D-Link · DIR-816version=1.10CNB05

Published CVSS scores

9.3VulDB CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8VulDB CNACVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8VulDB CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0VulDB CNAAV:N/AC:L/Au:N/C:C/I:C/A:C

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-121Stack-based Buffer Overflow
CWE-787Out-of-bounds Write
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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