LiveActive security incident?Get immediate response
CVE Record

CVE-2021-35395: Realtek Jungle SDK version v2.x up to v3.4.14B provides an HTTP web server exposing a management interface...

Realtek Jungle SDK version v2.x up to v3.4.14B provides an HTTP web server exposing a management interface that can be used to configure the access point. Two versions of this management interface exists: one based on Go-Ahead named webs and another based on Boa named boa. Both of them are affected by these vulnerabilities. Specifically, these binaries are vulnerable to the following issues: - stack buffer overflow in formRebootCheck due to unsafe copy of submit-url parameter - stack buffer overflow in formWsc due to unsafe copy of submit-url parameter - stack buffer overflow in formWlanMultipleAP due to unsafe copy of submit-url parameter - stack buffer overflow in formWlSiteSurvey due to unsafe copy of ifname parameter - stack buffer overflow in formStaticDHCP due to unsafe copy of hostname parameter - stack buffer overflow in formWsc due to unsafe copy of 'peerPin' parameter - arbitrary command execution in formSysCmd via the sysCmd parameter - arbitrary command injection in formWsc via the 'peerPin' parameter Exploitability of identified issues will differ based on what the end vendor/manufacturer did with the Realtek SDK webserver. Some vendors use it as-is, others add their own authentication implementation, some kept all the features from the server, some remove some of them, some inserted their own set of features. However, given that Realtek SDK implementation is full of insecure calls and that developers tends to re-use those examples in their custom code, any binary based on Realtek SDK webserver will probably contains its own set of issues on top of the Realtek ones (if kept). Successful exploitation of these issues allows remote attackers to gain arbitrary code execution on the device.

CriticalCVSS 9.8Known exploitedUpdated
Glexia's TakeHuman reviewedcritical

Security readout for executives and security teams

Plain-English summary

CVE-2021-35395 is a critical supply-chain vulnerability in Realtek’s Jungle SDK web management server used by downstream device makers. If a product includes the affected SDK components, a remote attacker may gain code execution on the device. Exposure depends heavily on each manufacturer’s firmware choices.

Executive priority

Treat this as urgent for network-edge and embedded devices because exploitation is recognized by CISA KEV and impact can be full device compromise. The main business risk is hidden exposure through third-party firmware reuse rather than a clearly named product list.

Technical view

Realtek Jungle SDK v2.x through v3.4.14B includes vulnerable Boa and GoAhead-based management interfaces. Reported issues include multiple stack buffer overflows and command execution or injection paths in form handlers. CVSS is 9.8 with network attack vector, no privileges, and no user interaction.

Likely exposure

Most likely exposure is embedded networking or IoT firmware that reused Realtek’s affected APRouter webserver code. The source bundle does not identify specific end-vendor products, so asset teams must validate by firmware lineage, vendor advisories, and device management interface behavior.

Exploitation context

CISA KEV listing indicates known exploited vulnerability status for CVE-2021-35395. Public sources also describe remote code execution impact. The provided evidence does not establish which specific brands, models, or firmware builds are exploitable in a given environment.

Researcher notes

Do not assume every Realtek-based device is affected or exploitable. The CVE description states exploitability varies by OEM authentication, feature removal, and customization. Focus research on firmware provenance, retained form handlers, exposed management services, and vendor-specific advisories.

Mitigation direction

  • Check Realtek and OEM advisories for firmware guidance specific to each device model.
  • Apply vendor firmware updates that explicitly address CVE-2021-35395, where available.
  • Limit web management interfaces to trusted administrative networks while exposure is assessed.
  • Remove or replace unsupported devices with no vendor remediation path.
  • Prioritize internet-facing or untrusted-network-accessible management interfaces first.

Validation and detection

  • Inventory devices and firmware that may contain Realtek Jungle SDK APRouter components.
  • Review vendor advisories for model-specific impact and fixed firmware versions.
  • Check whether HTTP management interfaces are reachable from untrusted networks.
  • Confirm whether Boa or GoAhead-based Realtek management code is present in firmware.
  • Track CISA KEV remediation expectations for affected assets in scope.
Prepared
Reviewed
Confidence
high
Sources
5

Michael Williams reviewed this cited source version on .

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-35395 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
Yes
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
5Source links

CISA KEV status

Status
Known exploited
Source
CISA / ADP
Date added
Not provided

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2021-35395Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.