CVE-2025-9938Public exploitNetwork attack vector

Authenticated code execution via unchecked sprintf

Published Sep 3, 2025 · Updated Sep 3, 2025

Stack-based buffer overflow in D-Link DI-8400 firmware 16.07.26A1 allows remote authenticated users to execute code via an HTTP request. The yyxz_dlink_asp handler for /yyxz.asp passes the untrusted id parameter to sprintf with a yyxz_%s format and a fixed-size stack buffer, without validating its length. Access to the web management interface and valid credentials are required; successful exploitation can take control of the device or crash and reboot its HTTP service.

CVSS severity8.8
High
EPSS probability1.51%
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 DI-8400 firmware 16.07.26A1 allows remote authenticated users to execute code via an HTTP request. The yyxz_dlink_asp handler for /yyxz.asp passes the untrusted id parameter to sprintf with a yyxz_%s format and a fixed-size stack buffer, without validating its length. Access to the web management interface and valid credentials are required; successful exploitation can take control of the device or crash and reboot its HTTP service.

The record

CVE
CVE-2025-9938
Published
Sep 3, 2025
Updated
Sep 3, 2025
Vendor
D-Link
Product
DI-8400
Classifications
CWE-121, CWE-119, CWE-787, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 3, 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=16.07.26A1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

D-Link · DI-8400version=16.07.26A1

Published CVSS scores

7.4VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
8.8VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.0VulDBAV:N/AC:L/Au:S/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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