Is CVE-2026-36779 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-36779 being exploited in the wild.

How severe is CVE-2026-36779?

Informational severity, with a CVSS score of 7.5, published 9 June 2026.

Which products and versions are affected?

Tenda O3 Wireless Router v1.0.0.5(4180).

Is there a fix for CVE-2026-36779?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-36779 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-36779?

Check whether you run Tenda O3 Wireless Router at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-36779: Tenda O3 Wireless Router stack overflow in fromVirtualSer

CVE-2026-36779 · Severity: info · CVSS 7.5 · Published 2026-06-09

The Tenda O3 Wireless Router, used for long-range outdoor wireless networking, contains a security flaw in its web management interface. By sending a specially crafted web request to the device, an attacker can cause the router to crash or reboot. This results in a denial of service, disrupting internet connectivity and network operations for all connected users.

Technologies: Tenda O3 Wireless Router. Vendors: Tenda.

Quick answers

Is CVE-2026-36779 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-36779 being exploited in the wild.
How severe is CVE-2026-36779?: Informational severity, with a CVSS score of 7.5, published 9 June 2026.
Which products and versions are affected?: Tenda O3 Wireless Router v1.0.0.5(4180).
Is there a fix for CVE-2026-36779?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-36779 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-36779?: Check whether you run Tenda O3 Wireless Router at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

Multiple stack-based buffer overflows exist in the 'fromVirtualSer' CGI handler of the Tenda O3 router (firmware v1.0.0.5). The vulnerability is located in the 'fromVirtualSer' function, where user-supplied parameters (puVar2, puVar1, __s2, __s1_00, and puVar3) are retrieved via 'websGetVar' and subsequently passed to 'sprintf' without length validation. An attacker can exploit this by sending a crafted HTTP request with overly long strings in these parameters to overwrite the stack. While the primary reported impact is a Denial of Service (DoS) through device crashes, stack exhaustion of this nature often carries a risk of arbitrary code execution. The vulnerability is reachable over the network via the web management interface.

Affected products

Tenda O3 Wireless Router v1.0.0.5(4180)

Timeline

2026-03-10: other: CVE request submitted to MITRE
2026-06-06: disclosed: Public disclosure
2026-06-09: advisory: NVD published date

References

https://github.com/xhh0124/SemVulLLM/tree/main/O3/fromVirtualSer

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.