Is CVE-2026-1623 actively exploited?

Yes. Previdian has observed exploitation attempts targeting this CVE. Confidence is confirmed.

What exploitation activity has Previdian observed?

Previdian sensors have observed 3 exploitation attempts, 2 unique attacker IPs, and 2 countries targeting CVE-2026-1623. First observed Jul 30, 2026; last observed Oct 10, 2026.

Which versions are affected?

CVE-2026-1623 affects Totolink A7000R. Reported affected version: 4.1cu.4154.

How should organizations remediate it?

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment. A Previdian virtual patch is available for temporary WAF compensating controls while remediation is underway.

No. CVE-2026-1623 is not currently listed in CISA KEV.

Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-1623

Totolink A7000R cstecgi.cgi setUpgradeFW command injection

Totolink / A7000R · 4.1cu.4154

Watch CVE-2026-1623 Browse KEV feed

Severity: CVSS 5.3 · Medium
Confidence: Confirmed
Exploit status: Observed in sensors
EPSS: 2.4%
First observed: 30 Jul 2026
Last observed: 10 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-1623 is Totolink A7000R cstecgi.cgi setUpgradeFW command injection. A weakness has been identified in Totolink A7000R 4.1cu.4154. Impacted is the function setUpgradeFW of the file /cgi-bin/cstecgi.cgi. This...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence.

Who is affected?

Totolink / A7000R 4.1cu.4154.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

A weakness has been identified in Totolink A7000R 4.1cu.4154

A weakness has been identified in Totolink A7000R 4.1cu.4154. Impacted is the function setUpgradeFW of the file /cgi-bin/cstecgi.cgi. This manipulation of the argument FileName causes command injection.

The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks.

Vendor Product Affected Status

Totolink Affected

A7000R

4.1cu.4154

Affected

View vendor advisory

Published: 29 Jan 2026
Exploitation Reported: 30 Jul 2026
Attack vector: Remote
Complexity: Low
Privileges: Low
User interaction: None

CVE References

CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-1623
GitHub — xyh4ck/iot_poc github.com · Patch https://github.com/xyh4ck/iot_poc/blob/main/TOTOLINK/A7000R/04_RCE_se...
GitHub — xyh4ck/iot_poc github.com · Patch https://github.com/xyh4ck/iot_poc/blob/main/TOTOLINK/A7000R/04_RCE_se...
Submit #740767 | TOTOLINK A7000R V4.1cu.4154 Command Injection vuldb.com · Third-Party Advisory https://vuldb.com/?submit.740767
VDB-343382 | Totolink A7000R cstecgi.cgi setUpgradeFW command injection vuldb.com · Technical Description https://vuldb.com/?id.343382
Product — totolink.net totolink.net · Product https://www.totolink.net/
VDB-343382 | CTI Indicators (IOB, IOC, TTP, IOA) vuldb.com · Signature https://vuldb.com/?ctiid.343382

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Previdian

Recorded 30 Jul 2026

Previdian independently recorded this as exploited after first seeing it in honeypot sensors.

Active exploitation observed

Previdian sensor

First observed 30 Jul 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Proof of concept available

Recorded 16 Jan 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access

Source	Added
Previdian Sensors First	2026-07-30 05:53 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

Attempts observed

Unique attacker IPs

Attacker countries

IN · NL

Sensors observed

CVE-2026-1623 exploitation attempts over the last 76 days

Daily events observed by Previdian sensors

Updated 12 Oct 2026

29 Jul 14 Aug 30 Aug 15 Sep 12 Oct

First observed 30 Jul 2026 · Last observed 10 Oct 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts: 1; 1; 1

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

Previdian virtual patch guidance is available for this CVE.

AWS WAF Cloudflare ModSecurity

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Virtual Patch Detail

Compensating WAF rules for this CVE.

Available

Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to Previdian Enterprise users.

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Risk and context

Severity, weaknesses, and research context

CVSS v4.0

5.3 Medium

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

EPSS

2.4%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') CWE-74 Improper Neutralization of Special Elements used in a Command ('Command Injection') CWE-77

All CVSS Scores

CVSS v4.0 5.3 Medium

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

CVSS v3.1 6.3 Medium

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

CVSS v3.0 6.3 Medium

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R

CVSS v2.0 6.5 Medium

AV:N/AC:L/Au:S/C:P/I:P/A:P

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

04_RCE_setUpgradeFW_RCE.md

public · Created 2026-01-16 07:53:00 UTC

Timeline

From disclosure to observed exploitation

10 Oct 2026
19:18 UTC

Virtual patch available

Compensating WAF rule available to block exploitation
30 Jul 2026
00:27 UTC

Indicators of compromise added (2)

Indicators of compromise recorded
30 Jul 2026
00:27 UTC

Observed by Previdian sensors

Evidence-backed exploitation signal
29 Jan 2026
20:32 UTC

CVE published

Vulnerability disclosed publicly
29 Jan 2026
14:39 UTC

CVE ID reserved

Identifier reserved by the CNA
16 Jan 2026
07:53 UTC

Public PoC available

Public proof-of-concept code published

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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Evidence confidence and provenance
First-party sensor telemetry
PoC and scanner references
Affected versions and enrichment
Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-1623

Free JSON includes basic KEV fields

{
  "cve_id": "CVE-2026-1623",
  "confidence": "Confirmed",
  "cvss_score": 5.3,
  "cvss_estimated": false,
  "epss_score": 0.02424,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 3, "sensors": 2 }
}