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Vulnerability record · CVE-2021-27251 · published 14 April 2021

CVE-2021-27251: Netgear br200 firmware cleartext transmission vulnerability

Netgear · Br200 Firmware

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR Nighthawk R7800. Authentication is not required to exploit this vulnerability The specific flaw exists within handling of firmware updates. The issue results from a fallback to a insecure protocol to deliver updates. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-12308.

8.8 CVSS 3.1 High EPSS 0.73% · top 46.6% CWE-319 · Cleartext transmission
8.8CVSS 3.1 base score, v2 8.3
0.73%EPSS exploitation probability, 30 days
NoNot in CISA KEV
43Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR Nighthawk R7800. Authentication is not required to exploit this vulnerability The specific flaw exists within handling of firmware updates. The issue results from a fallback to a insecure protocol to deliver updates. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-12308.

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

Affected products

43 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://kb.netgear.com/000062883/Security-Advisory-for-Multiple-Vulnerabilities-on-Some-Routers-Satellites-and-Extenders PatchVendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-247/ Third Party AdvisoryVDB Entry
https://kb.netgear.com/000062883/Security-Advisory-for-Multiple-Vulnerabilities-on-Some-Routers-Satellites-and-Extenders PatchVendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-247/ Third Party AdvisoryVDB Entry

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2016-10174NETGEAR router buffer overflow in hidden_lang_avi parameterThe NETGEAR WNR2000v5 router contains a buffer overflow in the hidden_lang_avi parameter when invoking the URL /apply.cgi?/lang_check.html. An unauth…KEVEPSS 83%analysed9.8CVE-2021-45658Netgear d7800 firmware injection vulnerabilityCertain NETGEAR devices are affected by server-side injection. This affects D7800 before 1.0.1.58, DM200 before 1.0.0.66, EX2700 before 1.0.1.56, EX6…EPSS 0.82%9.8CVE-2021-45618Netgear d7800 firmware command injection vulnerabilityCertain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects D7800 before 1.0.1.64, EX6200v2 before 1.0.1.8…EPSS 2.0%9.8CVE-2021-45619Netgear ex6250 firmware command injection vulnerabilityCertain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects EX6200v2 before 1.0.1.86, EX6250 before 1.0.0.…EPSS 2.5%9.8CVE-2021-45608Netgear d7800 firmware integer overflow vulnerabilityCertain D-Link, Edimax, NETGEAR, TP-Link, Tenda, and Western Digital devices are affected by an integer overflow by an unauthenticated attacker. Remo…EPSS 2.5%9.8CVE-2021-38529Netgear d7800 firmware command injection vulnerabilityCertain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects D7800 before 1.0.1.56, R7800 before 1.0.2.68, …EPSS 1.7%9.8CVE-2021-38527Netgear cbr40 firmware command injection vulnerabilityCertain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR40 before 2.5.0.14, EX6100v2 before 1.0.1.9…EPSS 1.7%9.8CVE-2021-38516Netgear d6220 firmware vulnerabilityCertain NETGEAR devices are affected by lack of access control at the function level. This affects D6220 before 1.0.0.48, D6400 before 1.0.0.82, D700…EPSS 1.3%

Source: NIST National Vulnerability Database (record CVE-2021-27251), CISA KEV, FIRST EPSS (scores of 2026-10-16). This page is refreshed as NVD updates the record.