CVE-2020-27861: This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NE
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HIGH 8.8UPGRADEUPGRADEUPGRADE
CVE-2020-27861 is a high-severity flaw (CVSS 8.8) affecting cbk40 firmware, cbk43 firmware, cbr40 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR Orbi 2.5.1.16 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the UA_Parser utility. A crafted Host Name option in a DHCP request can trigger execution of a system call composed from a user-supplied string. An attacker can leverage this vulnerability to execute code in the conte
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
Published CVE record published
Updated Record last modified
netgear cbk40 firmware UPGRADE
Affected: < 2.6.1.38
Fixed in: 2.6.1.38
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 cbk43 firmware UPGRADE
Affected: < 2.6.1.38
Fixed in: 2.6.1.38
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 cbr40 firmware UPGRADE
Affected: < 2.6.1.38
Fixed in: 2.6.1.38
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 ex6200 firmware UPGRADE
Affected: < 1.0.1.82
Fixed in: 1.0.1.82
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 ex7700 firmware UPGRADE
Affected: < 1.0.0.210
Fixed in: 1.0.0.210
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 ex8000 firmware UPGRADE
Affected: < 1.0.1.224
Fixed in: 1.0.1.224
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 sourceNVD · 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-2020-27861?
cbk40 firmware: upgrade to 2.6.1.38; cbk43 firmware: upgrade to 2.6.1.38; cbr40 firmware: upgrade to 2.6.1.38. Exact commands for each OS are on this page.
Is CVE-2020-27861 being exploited?
CVE-2020-27861 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-2020-27861 affect?
CVE-2020-27861 affects cbk40 firmware, cbk43 firmware, cbr40 firmware. Severity is high (CVSS 8.8). This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR Orbi 2.5.1.16 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the UA_
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