Critical Memory corruption exploit reference

CVE-2026-3703 — Wavlink NU516U1 login.cgi sub_401A10 out-of-bounds write

A flaw has been found in Wavlink NU516U1 251208. This affects the function sub_401A10 of the file /cgi-bin/login.cgi. Executing a manipulation of the argument ipaddr can lead to out-of-bounds write. The attack may be performed from remote. The exploit has been published and may be used. Upgrading the affected component is recommended. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

Published Mar 8, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: VulDB

Moderate

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 1.3% (30-day exploitation probability)+10
Technical severity (critical)+10
CISA SSVC: exploitation "poc"+5
Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

1.26%

ahead of 69% of scored CVEs · Oct 14, 2026

Affects

Wavlink

NU516U1 and 1 more

CVSS base

9.8

Critical · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Proof of concept

none · proof-of-concept · active

Automatable

Yes

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Wavlink NU516U1, Wavlink Wl-nu516u1 Firmware).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Wavlink	NU516U1	version 251208	Vulnerable	CVE Program (cve.org) e CISA ADP
Wavlink	Wl-nu516u1 Firmware	version 251208	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
9.3	CVSS 4.0	Critical	—	—	VulDB via CVE Program (cve.org) e CISA ADP
8.9	CVSS 4.0	High	—	—	cna@vuldb.com via NIST National Vulnerability Database
9.8	CVSS 3.1	Critical	3.9	5.9	cna@vuldb.com via NIST National Vulnerability Database
9.8	CVSS 3.1	Critical	—	—	VulDB via CVE Program (cve.org) e CISA ADP
9.8	CVSS 3.0	Critical	—	—	VulDB via CVE Program (cve.org) e CISA ADP
10.0	CVSS 2.0	High	10.0	10.0	cna@vuldb.com via NIST National Vulnerability Database
10.0	CVSS 2.0	High	—	—	VulDB via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: cna@vuldb.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-119 · Buffer Errors (Improper Restriction of Operations within Memory Bounds)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 1.26%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products added · wavlink/nu516u1
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 9.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Mar 8, 2026 · VulDB

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

6 on the record

github.com/Wlz1112/Wavlink-NU516U1-V251208-/blob/main/ipaddr.md
Exploit, Vendor Advisory, exploit, NIST National Vulnerability Database
github.com/Wlz1112/Wavlink-NU516U1-V251208-/blob/main/ipaddr.md
Exploit, Vendor Advisory, related, NIST National Vulnerability Database
dl.wavlink.com/firmware/RD/WINSTAR_NU516U1-WO-A-2026-02-27-2fcf6ae-mt7628-squashfs-s
Broken Link, patch, NIST National Vulnerability Database
vuldb.com/
Third Party Advisory, VDB Entry, vdb-entry, technical-description, NIST National Vulnerability Database
vuldb.com/
Third Party Advisory, VDB Entry, third-party-advisory, NIST National Vulnerability Database
vuldb.com/
Permissions Required, VDB Entry, signature, permissions-required, NIST National Vulnerability Database

Elsewhere on this site

Wavlink
every CVE for this vendor

Memory corruption
same class

CWE-119
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-8230 Wavlink NU516U1 login.cgi sys_login1 os command injection May 10, 2026
High CVE-2026-8227 Wavlink NU516U1 adm.cgi wzdapMesh os command injection May 10, 2026
High CVE-2026-8228 Wavlink NU516U1 wireless.cgi advance os command injection May 10, 2026
High CVE-2026-8229 Wavlink NU516U1 wireless.cgi WifiBasic os command injection May 10, 2026
High CVE-2026-8192 Wavlink NU516U1 adm.cgi wzdap os command injection May 9, 2026
High CVE-2026-8191 Wavlink NU516U1 adm.cgi wifi_region os command injection May 9, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-3703 is "Wavlink NU516U1 login.cgi sub_401A10 out-of-bounds write", rated Critical. It affects NU516U1 (Wavlink); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. EPSS 1.26% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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