CVE-2021-38527 [High] | Code Injection in Cbr40 Firmware

Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR40 before 2.5.0.14, EX6100v2 before 1.0.1.98, EX6150v2 before 1.0.1.98, EX6250 before 1.0.0.132, EX6400 before 1.0.2.158, EX6400v2 before 1.0.0.132, EX6410 before 1.0.0.132, EX6420 before 1.0.0.132, EX7300 before 1.0.2.158, EX7300v2 before 1.0.0.132, EX7320 before 1.0.0.132, EX7700 before 1.0.0.216, EX8000 before 1.0.1.232, R7800 before 1.0.2.78, RBK12 before 2.6.1.44, RBR10 before 2.6.1.44, RBS10 before 2.6.1.44, RBK20 before 2.6.1.38, RBR20 before 2.6.1.36, RBS20 before 2.6.1.38, RBK40 before 2.6.1.38, RBR40 before 2.6.1.36, RBS40 before 2.6.1.38, RBK50 before 2.6.1.40, RBR50 before 2.6.1.40, RBS50 before 2.6.1.40, RBK752 before 3.2.16.6, RBR750 before 3.2.16.6, RBS750 before 3.2.16.6, RBK852 before 3.2.16.6, RBR850 before 3.2.16.6, RBS850 before 3.2.16.6, RBS40V before 2.6.2.4, RBS50Y before 2.6.1.40, RBW30 before 2.6.2.2, and XR500 before 2.3.2.114.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	3.10%	1.69%	-1.42%
2	2026-03-19	2.46%	3.10%	+0.64%
3	2025-11-21	—	2.46%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

3.10%

1.69%

-1.42%

2026-03-19

2.46%

3.10%

+0.64%

2025-11-21

—

2.46%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.1	3.1	HIGH	`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N` Click to expand Attack vector (AV:A) Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:N) Service keeps running; no real outage angle.	2.8	5.2	[email protected]
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.9	[email protected]
10.0	2.0	HIGH	`AV:N/AC:L/Au:N/C:C/I:C/A:C` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:C) Complete confidentiality impact. Integrity impact (I:C) Complete integrity impact. Availability impact (A:C) Complete availability impact.	10.0	10.0	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.1

3.1

HIGH

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

Attack vector (AV:A): Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N): Service keeps running; no real outage angle.

2.8

5.2

[email protected]

9.8

3.1

CRITICAL

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

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.9

[email protected]

10.0

2.0

HIGH

AV:N/AC:L/Au:N/C:C/I:C/A:C Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:C): Complete confidentiality impact.
Integrity impact (I:C): Complete integrity impact.
Availability impact (A:C): Complete availability impact.

10.0

[email protected]

Affected software / configurations for CVE-2021-38527

Vendor	Product	Version	Raw CPE
netgear	cbr40_firmware	< 2.5.0.14	cpe:2.3:o:netgear:cbr40_firmware::::::::
netgear	ex6100_firmware	< 1.0.1.98	cpe:2.3:o:netgear:ex6100_firmware::::::::
netgear	ex6150_firmware	< 1.0.1.98	cpe:2.3:o:netgear:ex6150_firmware::::::::
netgear	ex6250_firmware	< 1.0.0.132	cpe:2.3:o:netgear:ex6250_firmware::::::::
netgear	ex6400_firmware	< 1.0.2.158	cpe:2.3:o:netgear:ex6400_firmware::::::::
netgear	ex6400_firmware	< 1.0.0.132	cpe:2.3:o:netgear:ex6400_firmware::::::::
netgear	ex6410_firmware	< 1.0.0.132	cpe:2.3:o:netgear:ex6410_firmware::::::::
netgear	ex6420_firmware	< 1.0.0.132	cpe:2.3:o:netgear:ex6420_firmware::::::::
netgear	ex7300_firmware	< 1.0.2.158	cpe:2.3:o:netgear:ex7300_firmware::::::::
netgear	ex7320_firmware	< 1.0.0.132	cpe:2.3:o:netgear:ex7320_firmware::::::::
netgear	ex7700_firmware	< 1.0.0.216	cpe:2.3:o:netgear:ex7700_firmware::::::::
netgear	ex8000_firmware	< 1.0.1.232	cpe:2.3:o:netgear:ex8000_firmware::::::::
netgear	r7800_firmware	< 1.0.2.78	cpe:2.3:o:netgear:r7800_firmware::::::::
netgear	rbk12_firmware	< 2.6.1.44	cpe:2.3:o:netgear:rbk12_firmware::::::::
netgear	rbr10_firmware	< 2.6.1.44	cpe:2.3:o:netgear:rbr10_firmware::::::::
netgear	rbs10_firmware	< 2.6.1.44	cpe:2.3:o:netgear:rbs10_firmware::::::::
netgear	rbk20_firmware	< 2.6.1.38	cpe:2.3:o:netgear:rbk20_firmware::::::::
netgear	rbr20_firmware	< 2.6.1.36	cpe:2.3:o:netgear:rbr20_firmware::::::::
netgear	rbs20_firmware	< 2.6.1.38	cpe:2.3:o:netgear:rbs20_firmware::::::::
netgear	rbk40_firmware	< 2.6.1.38	cpe:2.3:o:netgear:rbk40_firmware::::::::
netgear	rbr40_firmware	< 2.6.1.36	cpe:2.3:o:netgear:rbr40_firmware::::::::
netgear	rbs40_firmware	< 2.6.1.38	cpe:2.3:o:netgear:rbs40_firmware::::::::
netgear	rbk50_firmware	< 2.6.1.40	cpe:2.3:o:netgear:rbk50_firmware::::::::
netgear	rbr50_firmware	< 2.6.1.40	cpe:2.3:o:netgear:rbr50_firmware::::::::
netgear	rbs50_firmware	< 2.6.1.40	cpe:2.3:o:netgear:rbs50_firmware::::::::
netgear	rbk752_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbk752_firmware::::::::
netgear	rbr750_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbr750_firmware::::::::
netgear	rbs750_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbs750_firmware::::::::
netgear	rbk852_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbk852_firmware::::::::
netgear	rbr850_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbr850_firmware::::::::
netgear	rbs850_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbs850_firmware::::::::
netgear	rbs40v_firmware	< 2.6.2.4	cpe:2.3:o:netgear:rbs40v_firmware::::::::
netgear	rbs50y_firmware	< 2.6.1.40	cpe:2.3:o:netgear:rbs50y_firmware::::::::
netgear	rbw30_firmware	< 2.6.2.2	cpe:2.3:o:netgear:rbw30_firmware::::::::
netgear	xr500_firmware	< 2.3.2.114	cpe:2.3:o:netgear:xr500_firmware::::::::

References for CVE-2021-38527

URL	Tags
https://kb.netgear.com/000063778/Security-Advisory-for-Pre-Authentication-Command-Injection-on-Some-Extenders-Routers-and-WiFi-Systems-PSV-2020-0025	Vendor Advisory

URL

CVE-2021-38527

Exploit prediction scoring system (EPSS) score for CVE-2021-38527

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38527

Weakness enumeration for CVE-2021-38527

Affected software / configurations for CVE-2021-38527

References for CVE-2021-38527