CVE & CISA-KEV Catalog

CVE-2021-34991

HIGHEPSS 92th pctl
8.8
CVSS v3
NVD

Description

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400v2 1.0.4.106_10.0.80 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the UPnP service, which listens on TCP port 5000 by default. When parsing the uuid request header, the process does not properly validate the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-14110.

CWE-121Stack-based Buffer OverflowCWE-787Out-of-bounds Write

How to fix

Remediation Available
cax80 firmwareNVD
Affected:< 2.1.3.5Fixed in:2.1.3.5CVE-2021-34991derived from NVD
d6220 firmwareNVD
Affected:< 1.0.0.76Fixed in:1.0.0.76CVE-2021-34991derived from NVD
d6400 firmwareNVD
Affected:< 1.0.0.108Fixed in:1.0.0.108CVE-2021-34991derived from NVD
d7000v2 firmwareNVD
Affected:< 1.0.0.76Fixed in:1.0.0.76CVE-2021-34991derived from NVD
dc112a firmwareNVD
Affected:< 1.0.0.62Fixed in:1.0.0.62CVE-2021-34991derived from NVD
dgn2200v4 firmwareNVD
Affected:< 1.0.0.126Fixed in:1.0.0.126CVE-2021-34991derived from NVD
ex3700 firmwareNVD
Affected:< 1.0.0.94Fixed in:1.0.0.94CVE-2021-34991derived from NVD
ex3800 firmwareNVD
Affected:< 1.0.0.94Fixed in:1.0.0.94CVE-2021-34991derived from NVD
ex6120 firmwareNVD
Affected:< 1.0.0.66Fixed in:1.0.0.66CVE-2021-34991derived from NVD
ex6130 firmwareNVD
Affected:< 1.0.0.66Fixed in:1.0.0.66CVE-2021-34991derived from NVD
r6400 firmwareNVD
Affected:< 1.0.1.76Fixed in:1.0.1.76CVE-2021-34991derived from NVD
r6400v2 firmwareNVD
Affected:< 1.0.4.120Fixed in:1.0.4.120CVE-2021-34991derived from NVD
r6700v3 firmwareNVD
Affected:< 1.0.4.120Fixed in:1.0.4.120CVE-2021-34991derived from NVD
r6900p firmwareNVD
Affected:< 1.3.3.142Fixed in:1.3.3.142CVE-2021-34991derived from NVD
r7000 firmwareNVD
Affected:< 1.0.11.128Fixed in:1.0.11.128CVE-2021-34991derived from NVD
r7000p firmwareNVD
Affected:< 1.3.3.142Fixed in:1.3.3.142CVE-2021-34991derived from NVD
r7100lg firmwareNVD
Affected:< 1.0.0.72Fixed in:1.0.0.72CVE-2021-34991derived from NVD
r7850 firmwareNVD
Affected:< 1.0.5.76Fixed in:1.0.5.76CVE-2021-34991derived from NVD
r7900p firmwareNVD
Affected:< 1.4.2.84Fixed in:1.4.2.84CVE-2021-34991derived from NVD
r7960p firmwareNVD
Affected:< 1.4.2.84Fixed in:1.4.2.84CVE-2021-34991derived from NVD
r8000 firmwareNVD
Affected:< 1.0.4.76Fixed in:1.0.4.76CVE-2021-34991derived from NVD
r8000p firmwareNVD
Affected:< 1.4.2.84Fixed in:1.4.2.84CVE-2021-34991derived from NVD
r8300 firmwareNVD
Affected:< 1.0.2.156Fixed in:1.0.2.156CVE-2021-34991derived from NVD
r8500 firmwareNVD
Affected:< 1.0.2.156Fixed in:1.0.2.156CVE-2021-34991derived from NVD
rax15 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax200 firmwareNVD
Affected:< 1.0.5.132Fixed in:1.0.5.132CVE-2021-34991derived from NVD
rax20 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax35v2 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax38v2 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax40v2 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax42 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax43 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax45 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax48 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax50 firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax50s firmwareNVD
Affected:< 1.0.4.100Fixed in:1.0.4.100CVE-2021-34991derived from NVD
rax75 firmwareNVD
Affected:< 1.0.5.132Fixed in:1.0.5.132CVE-2021-34991derived from NVD
rax80 firmwareNVD
Affected:< 1.0.5.132Fixed in:1.0.5.132CVE-2021-34991derived from NVD
raxe450 firmwareNVD
Affected:< 1.0.8.70Fixed in:1.0.8.70CVE-2021-34991derived from NVD
raxe500 firmwareNVD
Affected:< 1.0.8.70Fixed in:1.0.8.70CVE-2021-34991derived from NVD
rs400 firmwareNVD
Affected:< 1.5.1.80Fixed in:1.5.1.80CVE-2021-34991derived from NVD
wndr3400v3 firmwareNVD
Affected:< 1.0.1.42Fixed in:1.0.1.42CVE-2021-34991derived from NVD
wnr3500lv2 firmwareNVD
Affected:< 1.2.0.70Fixed in:1.2.0.70CVE-2021-34991derived from NVD
xr300 firmwareNVD
Affected:< 1.0.3.68Fixed in:1.0.3.68CVE-2021-34991derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorAdjacent
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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

Exploit Intelligence

5.67%probability of exploitation in 30 days
92ndpercentile

High risk: more likely to be exploited than 92% of all known CVEs.

References

Vendor Advisory1
Third-Party Advisory1

Related Vulnerabilities

Other CWE-121 (Stack-based Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2025-22457Critical9.0100%KEV + RansomFix
CVE-2025-0282Critical9.0100%KEV + Ransom-
CVE-2021-20038Critical9.8100%KEV + Ransom-
CVE-2009-0927High8.897%KEVFix
CVE-2020-10924High8.887%--
CVE-2022-20705Critical10.080%--
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.