CVE-2026-18589Public exploitNetwork attack vector

Root code execution via unbounded password copy

Published Aug 3, 2026 · Updated Aug 3, 2026

Stack-based buffer overflow in Wavlink WL-NU516U1 firmware 708c073-mt7628 allows remote attackers to execute code as root. The change_password function in nas.cgi passes the User1Passwd POST value to strcpy(), which copies it without a length check into a 52-byte stack buffer. A ret2libc proof of concept redirects control flow to system() as root; MeshMode=2 removes the credential gate, while other paths require authentication or CSRF reachability.

CVSS severity9.8
Critical
EPSS probability0.61%
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 WL-NU516U1 firmware 708c073-mt7628 allows remote attackers to execute code as root. The change_password function in nas.cgi passes the User1Passwd POST value to strcpy(), which copies it without a length check into a 52-byte stack buffer. A ret2libc proof of concept redirects control flow to system() as root; MeshMode=2 removes the credential gate, while other paths require authentication or CSRF reachability.

The record

CVE
CVE-2026-18589
Published
Aug 3, 2026
Updated
Aug 3, 2026
Vendor
Wavlink
Product
WL-NU516U1
Classifications
CWE-119, CWE-121, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=708c073-mt7628

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Wavlink · WL-NU516U1version=708c073-mt7628

Published CVSS scores

8.9VulDBCVSS: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
10.0VulDBAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8VulDBCVSS: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-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-121Stack-based 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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