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NVD / CVE Program· CNA mitre

CVE-2021-43662: totolink EX300_v2, ver V4.0.3c.140_B20210429 and A720R ,ver V4.1.5cu.470_B20200911 have an issue which causes uncontrolled resource…

MediumCVSS 6.5 · v3.1—No exploit No fix recorded

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.54% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

totolink EX300_v2, ver V4.0.3c.140_B20210429 and A720R ,ver V4.1.5cu.470_B20200911 have an issue which causes uncontrolled resource consumption.

Published
Mar 30, 2022
Updated
Jun 17, 2026
EPSS
0.5% · 46th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-43662

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
totolinkex300 v2 firmware
totolinkex300 v2
totolinka720r firmware
totolinka720r

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • totolink a720r firmware4.1.5cu.470_b20200911
  • totolink ex300 v2 firmware4.0.3c.140_b20210429

Same product

totolink: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-32449TOTOLINK EX300_V2 V4.0.3c.7484 was discovered to contain a command injection vulnerability via the langType parameter in the setLanguageCfg…
    45Plan
  • CVE-2022-25008totolink EX300_v2 V4.0.3c.140_B20210429 and EX1200T V4.1.2cu.5230_B20210706 does not contain an authentication mechanism.
    36Monitor
  • CVE-2021-43664totolink EX300_v2 V4.0.3c.140_B20210429 was discovered to contain a command injection vulnerability via the component…
    32Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2021-43661Mar 30, 2022 · totolink EX300_v2 V4.0.3c.140_B20210429 was discovered to contain a reflected cross-site scripting (XSS) vulnerability via the component…
    24Monitor
  • Later →CVE-2021-43663Mar 30, 2022 · totolink EX300_v2 V4.0.3c.140_B20210429 was discovered to contain a command injection vulnerability via the component cloudupdate_check.
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-770 · Allocation of Resources Without Limits or Throttling

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

All records