CVE-2021-34947 | NETGEAR R7800 net-cgi Out-Of-Bounds Write Remote Code Execution Vulnerability

NETGEAR R7800 net-cgi Out-Of-Bounds Write Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R7800 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the parsing of the soap_block_table file. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated data structure. An attacker can leverage this vulnerability to execute code in the context of root. . Was ZDI-CAN-13055.

Published: 2024-05-07 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-34947 is rated Moderate Risk (49.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.55%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-34947

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.39% 0.55% +0.16%
2 2025-11-21 0.29% 0.39% +0.10%
3 2025-11-18 — 0.29% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-34947

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.0 HIGH
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H 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:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]

Weakness enumeration for CVE-2021-34947

Affected software / configurations for CVE-2021-34947

Vendor Product Version Raw CPE
netgear d7800_firmware < 1.0.1.64 cpe:2.3:o:netgear:d7800_firmware:*:*:*:*:*:*:*:*
netgear ex2700_firmware < 1.0.1.66 cpe:2.3:o:netgear:ex2700_firmware:*:*:*:*:*:*:*:*
netgear ex6100_firmware < 1.0.1.106 cpe:2.3:o:netgear:ex6100_firmware:*:*:*:*:*:*:*:*
netgear ex6150_firmware < 1.0.1.106 cpe:2.3:o:netgear:ex6150_firmware:*:*:*:*:*:*:*:*
netgear ex6200_firmware < 1.0.1.86 cpe:2.3:o:netgear:ex6200_firmware:*:*:*:*:*:*:*:*
netgear ex6250_firmware < 1.0.0.146 cpe:2.3:o:netgear:ex6250_firmware:*:*:*:*:*:*:*:*
netgear ex6400_firmware < 1.0.2.164 cpe:2.3:o:netgear:ex6400_firmware:*:*:*:*:*:*:*:*
netgear ex6400v2_firmware < 1.0.0.146 cpe:2.3:o:netgear:ex6400v2_firmware:*:*:*:*:*:*:*:*
netgear ex6410_firmware < 1.0.0.146 cpe:2.3:o:netgear:ex6410_firmware:*:*:*:*:*:*:*:*
netgear ex6420_firmware < 1.0.0.146 cpe:2.3:o:netgear:ex6420_firmware:*:*:*:*:*:*:*:*
netgear ex6500v1_firmware < 1.0.0.146 cpe:2.3:o:netgear:ex6500v1_firmware:*:*:*:*:*:*:*:*
netgear ex7300_firmware < 1.0.2.164 cpe:2.3:o:netgear:ex7300_firmware:*:*:*:*:*:*:*:*
netgear ex7300v2_firmware < 1.0.0.146 cpe:2.3:o:netgear:ex7300v2_firmware:*:*:*:*:*:*:*:*
netgear ex7320_firmware < 1.0.0.146 cpe:2.3:o:netgear:ex7320_firmware:*:*:*:*:*:*:*:*
netgear ex7700_firmware < 1.0.0.222 cpe:2.3:o:netgear:ex7700_firmware:*:*:*:*:*:*:*:*
netgear ex8000_firmware < 1.0.1.238 cpe:2.3:o:netgear:ex8000_firmware:*:*:*:*:*:*:*:*
netgear lbr1020_firmware < 2.6.5.32 cpe:2.3:o:netgear:lbr1020_firmware:*:*:*:*:*:*:*:*
netgear lbr20_firmware < 2.6.5.32 cpe:2.3:o:netgear:lbr20_firmware:*:*:*:*:*:*:*:*
netgear r6700ax_firmware < 1.0.5.108 cpe:2.3:o:netgear:r6700ax_firmware:*:*:*:*:*:*:*:*
netgear r7800_firmware < 1.0.2.84 cpe:2.3:o:netgear:r7800_firmware:*:*:*:*:*:*:*:*
netgear r8900_firmware < 1.0.5.36 cpe:2.3:o:netgear:r8900_firmware:*:*:*:*:*:*:*:*
netgear r9000_firmware < 1.0.5.36 cpe:2.3:o:netgear:r9000_firmware:*:*:*:*:*:*:*:*
netgear rax10_firmware < 1.0.5.108 cpe:2.3:o:netgear:rax10_firmware:*:*:*:*:*:*:*:*
netgear rax120_firmware < 1.2.2.24 cpe:2.3:o:netgear:rax120_firmware:*:*:*:*:*:*:*:*
netgear rax120v2_firmware < 1.2.2.24 cpe:2.3:o:netgear:rax120v2_firmware:*:*:*:*:*:*:*:*
netgear rax70_firmware < 1.0.5.108 cpe:2.3:o:netgear:rax70_firmware:*:*:*:*:*:*:*:*
netgear rax78_firmware < 1.0.5.108 cpe:2.3:o:netgear:rax78_firmware:*:*:*:*:*:*:*:*
netgear rbr10_firmware < 2.7.4.24 cpe:2.3:o:netgear:rbr10_firmware:*:*:*:*:*:*:*:*
netgear rbr20_firmware < 2.7.4.24 cpe:2.3:o:netgear:rbr20_firmware:*:*:*:*:*:*:*:*
netgear rbr40_firmware < 2.7.4.24 cpe:2.3:o:netgear:rbr40_firmware:*:*:*:*:*:*:*:*
netgear rbr50_firmware < 2.7.4.24 cpe:2.3:o:netgear:rbr50_firmware:*:*:*:*:*:*:*:*
netgear rbs10_firmware < 2.7.4.24 cpe:2.3:o:netgear:rbs10_firmware:*:*:*:*:*:*:*:*
netgear rbs20_firmware < 2.7.4.24 cpe:2.3:o:netgear:rbs20_firmware:*:*:*:*:*:*:*:*
netgear rbs40_firmware < 2.7.4.24 cpe:2.3:o:netgear:rbs40_firmware:*:*:*:*:*:*:*:*
netgear rbs50_firmware < 2.7.4.24 cpe:2.3:o:netgear:rbs50_firmware:*:*:*:*:*:*:*:*
netgear rbs50y_firmware < 2.7.4.12 cpe:2.3:o:netgear:rbs50y_firmware:*:*:*:*:*:*:*:*
netgear wn3000rpv2_firmware < 1.0.0.88 cpe:2.3:o:netgear:wn3000rpv2_firmware:*:*:*:*:*:*:*:*
netgear wnr2000v5_firmware < 1.0.0.78 cpe:2.3:o:netgear:wnr2000v5_firmware:*:*:*:*:*:*:*:*
netgear xr450_firmware < 2.3.2.130 cpe:2.3:o:netgear:xr450_firmware:*:*:*:*:*:*:*:*
netgear xr500_firmware < 2.3.2.130 cpe:2.3:o:netgear:xr500_firmware:*:*:*:*:*:*:*:*
netgear xr700_firmware < 1.0.1.44 cpe:2.3:o:netgear:xr700_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-34947

cvelogic Threat Intelligence