CVE-2021-45639 [Medium] | XSS in Cbr40 Firmware

Certain NETGEAR devices are affected by reflected XSS. This affects CBR40 before 2.5.0.10, EAX20 before 1.0.0.32, EAX80 before 1.0.1.62, EX6120 before 1.0.0.64, EX6130 before 1.0.0.44, EX7000 before 1.0.1.104, EX7500 before 1.0.0.72, R7000 before 1.0.11.110, R7900 before 1.0.4.30, R7960P before 1.4.1.66, R8000 before 1.0.4.62, RAX200 before 1.0.2.102, XR300 before 1.0.3.50, EX3700 before 1.0.0.90, MR60 before 1.0.5.102, R7000P before 1.3.2.126, R8000P before 1.4.1.66, RAX20 before 1.0.1.64, RAX50 before 1.0.2.28, RAX80 before 1.0.3.102, EX3800 before 1.0.0.90, MS60 before 1.0.5.102, R6900P before 1.3.2.126, R7900P before 1.4.1.66, RAX15 before 1.0.1.64, RAX45 before 1.0.2.28, RAX75 before 1.0.3.102, RBR750 before 3.2.16.6, RBR850 before 3.2.16.6, RBS750 before 3.2.16.6, RBS850 before 3.2.16.6, RBK752 before 3.2.16.6, and RBK852 before 3.2.16.6.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.25%	0.60%	+0.35%
2	2025-03-30	0.39%	0.25%	-0.14%
3	2025-03-29	—	0.39%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.25%

0.60%

+0.35%

2025-03-30

0.39%

0.25%

-0.14%

2025-03-29

—

0.39%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.2	3.1	MEDIUM	`CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:L/I:L/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:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	2.1	2.7	[email protected]
6.1	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N` 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:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	2.8	2.7	[email protected]
4.3	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:N/I:P/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:N) No availability impact.	8.6	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.2

3.1

MEDIUM

CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:L/I:L/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:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

2.1

2.7

[email protected]

6.1

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N 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:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

2.8

2.7

[email protected]

4.3

2.0

MEDIUM

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

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:M): Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:N): No availability impact.

8.6

2.9

[email protected]

Affected software / configurations for CVE-2021-45639

Vendor	Product	Version	Raw CPE
netgear	cbr40_firmware	< 2.5.0.10	cpe:2.3:o:netgear:cbr40_firmware::::::::
netgear	eax20_firmware	< 1.0.0.32	cpe:2.3:o:netgear:eax20_firmware::::::::
netgear	eax80_firmware	< 1.0.1.62	cpe:2.3:o:netgear:eax80_firmware::::::::
netgear	ex6120_firmware	< 1.0.0.64	cpe:2.3:o:netgear:ex6120_firmware::::::::
netgear	ex6130_firmware	< 1.0.0.44	cpe:2.3:o:netgear:ex6130_firmware::::::::
netgear	ex7000_firmware	< 1.0.1.104	cpe:2.3:o:netgear:ex7000_firmware::::::::
netgear	ex7500_firmware	< 1.0.0.72	cpe:2.3:o:netgear:ex7500_firmware::::::::
netgear	r7000_firmware	< 1.0.11.110	cpe:2.3:o:netgear:r7000_firmware::::::::
netgear	r7900_firmware	< 1.0.4.30	cpe:2.3:o:netgear:r7900_firmware::::::::
netgear	r7960p_firmware	< 1.4.1.66	cpe:2.3:o:netgear:r7960p_firmware::::::::
netgear	r8000_firmware	< 1.0.4.62	cpe:2.3:o:netgear:r8000_firmware::::::::
netgear	rax200_firmware	< 1.0.2.102	cpe:2.3:o:netgear:rax200_firmware::::::::
netgear	xr300_firmware	< 1.0.3.50	cpe:2.3:o:netgear:xr300_firmware::::::::
netgear	ex3700_firmware	< 1.0.0.90	cpe:2.3:o:netgear:ex3700_firmware::::::::
netgear	mr60_firmware	< 1.0.5.102	cpe:2.3:o:netgear:mr60_firmware::::::::
netgear	r7000p_firmware	< 1.3.2.126	cpe:2.3:o:netgear:r7000p_firmware::::::::
netgear	r8000p_firmware	< 1.4.1.66	cpe:2.3:o:netgear:r8000p_firmware::::::::
netgear	rax20_firmware	< 1.0.1.64	cpe:2.3:o:netgear:rax20_firmware::::::::
netgear	rax50_firmware	< 1.0.2.28	cpe:2.3:o:netgear:rax50_firmware::::::::
netgear	rax80_firmware	< 1.0.3.102	cpe:2.3:o:netgear:rax80_firmware::::::::
netgear	ex3800_firmware	< 1.0.0.90	cpe:2.3:o:netgear:ex3800_firmware::::::::
netgear	ms60_firmware	< 1.0.5.102	cpe:2.3:o:netgear:ms60_firmware::::::::
netgear	r6900p_firmware	< 1.3.2.126	cpe:2.3:o:netgear:r6900p_firmware::::::::
netgear	r7900p_firmware	< 1.4.1.66	cpe:2.3:o:netgear:r7900p_firmware::::::::
netgear	rax15_firmware	< 1.0.1.64	cpe:2.3:o:netgear:rax15_firmware::::::::
netgear	rax45_firmware	< 1.0.2.28	cpe:2.3:o:netgear:rax45_firmware::::::::
netgear	rax75_firmware	< 1.0.3.102	cpe:2.3:o:netgear:rax75_firmware::::::::
netgear	rbr750_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbr750_firmware::::::::
netgear	rbr850_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbr850_firmware::::::::
netgear	rbs750_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbs750_firmware::::::::
netgear	rbs850_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbs850_firmware::::::::
netgear	rbk752_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbk752_firmware::::::::
netgear	rbk852_firmware	< 3.2.16.6	cpe:2.3:o:netgear:rbk852_firmware::::::::

References for CVE-2021-45639

URL	Tags
https://kb.netgear.com/000064460/Security-Advisory-for-Reflected-Cross-Site-Scripting-on-Some-Routers-Extenders-and-WiFi-Systems-PSV-2020-0121	Vendor Advisory

URL

CVE-2021-45639

Exploit prediction scoring system (EPSS) score for CVE-2021-45639

Common vulnerability scoring system (CVSS) metrics for CVE-2021-45639

Weakness enumeration for CVE-2021-45639

Affected software / configurations for CVE-2021-45639

References for CVE-2021-45639