How severe is CVE-2021-27257?

CVE-2021-27257 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-27257 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27257?

CVE-2021-27257 primarily affects Netgear Br200 Firmware. In total, 43 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-27257?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-27257 published?

CVE-2021-27257 was published on 2021-03-05 and last updated on 2026-06-17.

CVE-2021-27257

CVE-2021-27257 is a medium-severity vulnerability in Netgear Br200 Firmware with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-295.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 3.3
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Netgear Br200 Firmware
Published: 2021-03-05
Last modified: 2026-06-17

Description

This vulnerability allows network-adjacent attackers to compromise the integrity of downloaded information on affected installations of NETGEAR R7800 firmware version 1.0.2.76. Authentication is not required to exploit this vulnerability. The specific flaw exists within the downloading of files via FTP. The issue results from the lack of proper validation of the certificate presented by the server. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of root. Was ZDI-CAN-12362.

Frequently asked questions

What is CVE-2021-27257?: This vulnerability allows network-adjacent attackers to compromise the integrity of downloaded information on affected installations of NETGEAR R7800 firmware version 1.0.2.76. Authentication is not required to exploit this vulnerability. The specific flaw exists within the downloading of files via FTP. The issue results from the lack of proper validation of the certificate presented by the server. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of root. Was ZDI-CAN-12362.
How severe is CVE-2021-27257?: CVE-2021-27257 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-27257 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27257?: CVE-2021-27257 primarily affects Netgear Br200 Firmware. In total, 43 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-27257?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-27257 published?: CVE-2021-27257 was published on 2021-03-05 and last updated on 2026-06-17.

References

Affected products (43)

cpe:2.3:o:netgear:br200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:br500_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:d7800_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex6100v2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex6150v2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex6250_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex6400_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex6400v2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex6410_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex6420_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex7300_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex7300v2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex7320_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex7700_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:ex8000_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:lbr20_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:r7800_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:r8900_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:r9000_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk12_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk13_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk14_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk15_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk20_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk23_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk40_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk43_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk43s_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk44_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk50_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbk53_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbr10_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbr20_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbr40_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbr50_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbs10_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbs20_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbs40_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbs50_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:rbs50y_firmware:*:*:*:*:*:*:*:*

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