{"id":"CVE-2021-40847","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-40847","generatedAt":"2026-11-05T01:03:22.918Z","title":"The update process of the Circle Parental Control Service on various NETGEAR routers allows remote attackers to achieve remote code execution as root via a MitM attack.","description":"The update process of the Circle Parental Control Service on various NETGEAR routers allows remote attackers to achieve remote code execution as root via a MitM attack. While the parental controls themselves are not enabled by default on the routers, the Circle update daemon, circled, is enabled by default. This daemon connects to Circle and NETGEAR to obtain version information and updates to the circled daemon and its filtering database. However, database updates from NETGEAR are unsigned and downloaded via cleartext HTTP. As such, an attacker with the ability to perform a MitM attack on the device can respond to circled update requests with a crafted, compressed database file, the extraction of which gives the attacker the ability to overwrite executable files with attacker-controlled code. This affects R6400v2 1.0.4.106, R6700 1.0.2.16, R6700v3 1.0.4.106, R6900 1.0.2.16, R6900P 1.3.2.134, R7000 1.0.11.123, R7000P 1.3.2.134, R7850 1.0.5.68, R7900 1.0.4.38, R8000 1.0.4.68, and RS400 1.5.0.68.","published":"2021-09-21T18:15:07.000Z","lastModified":"2026-06-17T04:07:32.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-319"],"affected":["netgear/r6400v2 firmware","netgear/r6700 firmware","netgear/r6700v3 firmware","netgear/r6900 firmware","netgear/r6900p firmware","netgear/r7000 firmware","netgear/r7000p firmware","netgear/r7850 firmware","netgear/r7900 firmware","netgear/r8000 firmware","netgear/rs400 firmware"],"epss":{"score":0.10014,"percentile":0.9562,"date":"2026-11-03","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 10.0%, higher than 96% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"https://blog.grimm-co.com/2021/09/mama-always-told-me-not-to-trust.html","tags":["Exploit","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://kb.netgear.com/000064039/Security-Advisory-for-Remote-Code-Execution-on-Some-Routers-PSV-2021-0204","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://blog.grimm-co.com/2021/09/mama-always-told-me-not-to-trust.html","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://kb.netgear.com/000064039/Security-Advisory-for-Remote-Code-Execution-on-Some-Routers-PSV-2021-0204","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-40847","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}