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CVE-2021-45621: Certain NETGEAR devices are affected by command injection by an unauthenticated attacker

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CRITICAL 9.6UPGRADEUPGRADEUPGRADE

CVE-2021-45621 is a critical-severity flaw (CVSS 9.6) affecting cbr40 firmware, cbr750 firmware, eax20 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR40 before 2.5.0.24, CBR750 before 3.2.18.2, EAX20 before 1.0.0.58, EAX80 before 1.0.1.68, EX3700 before 1.0.0.94, EX3800 before 1.0.0.94, EX6120 before 1.0.0.64, EX6130 before 1.0.0.44, EX7000 before 1.0.1.104, EX7500 before 1.0.0.74, LAX20 before 1.1.6.28, MR60 before 1.0.6.116, MS60 before 1.0.6.116, R6300v2 before 1.0.4.52, R6400 before 1.

Why this priority

  • Critical severity

A fixed release or distro patch exists.

Risk facts

CVSS score9.6 (Critical)
Attack vectorAdjacent network
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance2.0% (top 19%)
CISA exploited listNo
WeaknessCWE-77
Published2021-12-26
Last modified2026-06-17
Publisher (CNA): MITRE · Vendor: netgear

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

Am I affected?

Timeline

netgear cbr40 firmware UPGRADE
Affected: < 2.5.0.24
Fixed in: 2.5.0.24
Safe to downgrade to: no unaffected older release
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.
netgear cbr750 firmware UPGRADE
Affected: < 3.2.18.2
Fixed in: 3.2.18.2
Safe to downgrade to: no unaffected older release
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.
netgear eax20 firmware UPGRADE
Affected: < 1.0.0.58
Fixed in: 1.0.0.58
Safe to downgrade to: no unaffected older release
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.
netgear eax80 firmware UPGRADE
Affected: < 1.0.1.68
Fixed in: 1.0.1.68
Safe to downgrade to: no unaffected older release
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.
netgear rax15 firmware UPGRADE
Affected: < 1.0.3.96
Fixed in: 1.0.3.96
Safe to downgrade to: no unaffected older release
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.
netgear rax20 firmware UPGRADE
Affected: < 1.0.3.96
Fixed in: 1.0.3.96
Safe to downgrade to: no unaffected older release
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-2021-45621?

cbr40 firmware: upgrade to 2.5.0.24; cbr750 firmware: upgrade to 3.2.18.2; eax20 firmware: upgrade to 1.0.0.58. Exact commands for each OS are on this page.

Is CVE-2021-45621 being exploited?

CVE-2021-45621 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-2021-45621 affect?

CVE-2021-45621 affects cbr40 firmware, cbr750 firmware, eax20 firmware. Severity is critical (CVSS 9.6). Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR40 before 2.5.0.24, CBR750 before 3.2.18.2, EAX20 before 1.0.0.58, EAX80 before 1.0.1.68, EX3700 before 1.0.0.94, EX3800 before 1.0.0.

How urgent is CVE-2021-45621?

Priority 54/100. Critical severity

Software pages

Netgear vulnerabilities

Related CVEs

References

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