How severe is CVE-2021-35393?

CVE-2021-35393 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-35393 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 70% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-35393?

CVE-2021-35393 affects Realtek Rtl819x Jungle Software Development Kit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-35393?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-35393 published?

CVE-2021-35393 was published on 2021-08-16 and last updated on 2026-06-17.

CVE-2021-35393

CVE-2021-35393 is a critical-severity vulnerability in Realtek Rtl819x Jungle Software Development Kit with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 70% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 70% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Realtek Rtl819x Jungle Software Development Kit
Published: 2021-08-16
Last modified: 2026-06-17

Description

Realtek Jungle SDK version v2.x up to v3.4.14B provides a 'WiFi Simple Config' server that implements both UPnP and SSDP protocols. The binary is usually named wscd or mini_upnpd and is the successor to miniigd. The server is vulnerable to a stack buffer overflow vulnerability that is present due to unsafe parsing of the UPnP SUBSCRIBE/UNSUBSCRIBE Callback header. Successful exploitation of this vulnerability allows remote unauthenticated attackers to gain arbitrary code execution on the affected device.

Frequently asked questions

What is CVE-2021-35393?: Realtek Jungle SDK version v2.x up to v3.4.14B provides a 'WiFi Simple Config' server that implements both UPnP and SSDP protocols. The binary is usually named wscd or mini_upnpd and is the successor to miniigd. The server is vulnerable to a stack buffer overflow vulnerability that is present due to unsafe parsing of the UPnP SUBSCRIBE/UNSUBSCRIBE Callback header. Successful exploitation of this vulnerability allows remote unauthenticated attackers to gain arbitrary code execution on the affected device.
How severe is CVE-2021-35393?: CVE-2021-35393 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-35393 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 70% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-35393?: CVE-2021-35393 affects Realtek Rtl819x Jungle Software Development Kit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-35393?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-35393 published?: CVE-2021-35393 was published on 2021-08-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:realtek:rtl819x_jungle_software_development_kit:*:*:*:*:*:*:*:*

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