CVE-2026-4861: A weakness has been identified in Wavlink WL-NU516U1 260227

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HIGH 8.8MITIGATE

CVE-2026-4861 is a high-severity flaw (CVSS 8.8) affecting wl-nu516u1 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A weakness has been identified in Wavlink WL-NU516U1 260227. This vulnerability affects the function ftext of the file /cgi-bin/nas.cgi. This manipulation of the argument Content-Length causes stack-based buffer overflow. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.9% (top 42%)
CISA exploited list	No
Weakness	CWE-119, CWE-121
Published	2026-03-26
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: wavlink

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-26 09:16 UTCPublished CVE record published
2026-06-17 10:57 UTCUpdated Record last modified

wavlink wl-nu516u1 firmware MITIGATE

Affected: m16u1_v260227

Fixed in: no fixed release known

Safe to downgrade to: a release before m16u1_v260227

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-4861?

wl-nu516u1 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-4861 being exploited?

CVE-2026-4861 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-4861 affect?

CVE-2026-4861 affects wl-nu516u1 firmware. Severity is high (CVSS 8.8). A weakness has been identified in Wavlink WL-NU516U1 260227. This vulnerability affects the function ftext of the file /cgi-bin/nas.cgi. This manipulation of the argument Content-Length causes stack-based buffer overflow. The attack can be

How urgent is CVE-2026-4861?

Priority 50/100. High severity; Public exploit reference

Related CVEs

CVE-2026-8188 MEDIUM 6.3 MITIGATE A vulnerability has been found in Wavlink NU516U1 M16U1_V240425
CVE-2026-8189 MEDIUM 6.3 MITIGATE A vulnerability was found in Wavlink NU516U1 M16U1_V240425
CVE-2026-8190 MEDIUM 6.3 MITIGATE A vulnerability was determined in Wavlink NU516U1 M16U1_V240425
CVE-2026-8191 MEDIUM 6.3 MITIGATE A vulnerability was identified in Wavlink NU516U1 M16U1_V240425
CVE-2026-8192 MEDIUM 6.3 MITIGATE A security flaw has been discovered in Wavlink NU516U1 M16U1_V240425

References

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