CVE-2026-3703Public exploitNetwork attack vector

Authenticated CGI-process crash via unbounded ipaddr formatting

Published Mar 8, 2026 · Updated Mar 8, 2026

Stack buffer overflow in Wavlink WL-NU516U1 251208 allows remote authenticated users to crash login.cgi via a long ipaddr value. In sub_401A10, sprintf writes the unbounded parameter into a 128-byte stack buffer after a character filter checks content but not length. A valid session cookie and the administrator password hash are required; the demonstrated consequence is a CGI-process crash, while code execution is unconfirmed.

CVSS severityUnavailable
Unscored
EPSS probability0.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in Wavlink WL-NU516U1 251208 allows remote authenticated users to crash login.cgi via a long ipaddr value. In sub_401A10, sprintf writes the unbounded parameter into a 128-byte stack buffer after a character filter checks content but not length. A valid session cookie and the administrator password hash are required; the demonstrated consequence is a CGI-process crash, while code execution is unconfirmed.

The record

CVE
CVE-2026-3703
Published
Mar 8, 2026
Updated
Mar 8, 2026
Vendor
Wavlink
Product
WL-NU516U1
Classifications
CWE-787, CWE-119, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 8, 2026Record 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=251208

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Wavlink · WL-NU516U1version=251208

Published CVSS scores

9.3VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
9.8VulDBCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
9.8VulDBCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
10.0VulDBAV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:OF/RC: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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