CVE-2024-39803Public exploitNetwork attack vector

Authenticated code execution via unbounded sprintf

Published Jan 14, 2025 · Updated Nov 3, 2025

Stack-based buffer overflow in Wavlink AC3000 M33A8.V5030.210505 allows remote authenticated users to execute arbitrary code via qos.cgi. The qos_settings() function passes the unbounded sel_mode POST value to sprintf when constructing a command in the 0x500-byte cmdtorun stack buffer. A valid session and network access to the administration interface are required; successful overflow permits return-address overwrite and code execution.

CVSS severity7.2
High
EPSS probability1.26%
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 Wavlink AC3000 M33A8.V5030.210505 allows remote authenticated users to execute arbitrary code via qos.cgi. The qos_settings() function passes the unbounded sel_mode POST value to sprintf when constructing a command in the 0x500-byte cmdtorun stack buffer. A valid session and network access to the administration interface are required; successful overflow permits return-address overwrite and code execution.

The record

CVE
CVE-2024-39803
Published
Jan 14, 2025
Updated
Nov 3, 2025
Vendor
Wavlink
Product
AC3000 Tri-band Wi-Fi Router
Classifications
CWE-120, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 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=M33A8.V5030.210505

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Wavlink · AC3000 Tri-band Wi-Fi Routerversion=M33A8.V5030.210505

Published CVSS scores

9.1Cisco TalosCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
7.2NVDCVSS:3.1/AV:N/AC:L/PR:H/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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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