CVE-2026-73673Public exploit

Persistent compromise via unauthenticated unsigned firmware upload

Published Aug 14, 2026 · Updated Aug 14, 2026

Missing authentication in Netis NC63 firmware V3.0.0.3327 allows remote attackers to upload unsigned firmware through the management interface. Boa authorizes any path containing .cgi, while netis.cgi dispatches upload_fw.cgi without enforcing the recorded session state; the updater checks only forgeable additive checksums and static product strings. Access normally requires adjacency to the router management interface, but successful firmware replacement grants persistent control of device traffic and operation.

CVSS severity8.7
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authentication in Netis NC63 firmware V3.0.0.3327 allows remote attackers to upload unsigned firmware through the management interface. Boa authorizes any path containing .cgi, while netis.cgi dispatches upload_fw.cgi without enforcing the recorded session state; the updater checks only forgeable additive checksums and static product strings. Access normally requires adjacency to the router management interface, but successful firmware replacement grants persistent control of device traffic and operation.

The record

CVE
CVE-2026-73673
Published
Aug 14, 2026
Updated
Aug 14, 2026
Vendor
Netis Systems Co., Ltd.
Product
Netis NC63
Classifications
CWE-306, T1601.001
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 14, 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=0 <=V3.0.0.3327

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Netis Systems Co., Ltd. · Netis NC63version=0 <=V3.0.0.3327

Published CVSS scores

8.8VulnCheckCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.7VulnCheckCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1601.001Patch System Image

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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