Is CVE-2026-85109 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-85109 being exploited in the wild.

How severe is CVE-2026-85109?

Critical severity, with a CVSS score of 9.8, published 3 September 2026.

Which products and versions are affected?

Tenda HG10 HG7_HG9_HG10re_300001138.

Is there a fix for CVE-2026-85109?

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-2026-85109 attacked?

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

Am I affected by CVE-2026-85109?

Check whether you run Tenda HG10 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-2026-85109: Tenda HG10 buffer overflow in Boa Web Server login handler

CVE-2026-85109 · Severity: critical · CVSS 9.8 · Published 2026-09-03

The Tenda HG10 router contains a web server component vulnerable to buffer overflow when processing login requests. An unauthenticated attacker can send a specially crafted HTTP request with an oversized username parameter to crash the device or potentially execute arbitrary code, disrupting network connectivity for all users relying on that router.

Technologies: Tenda HG10. Vendors: Tenda.

Quick answers

Is CVE-2026-85109 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-85109 being exploited in the wild.
How severe is CVE-2026-85109?: Critical severity, with a CVSS score of 9.8, published 3 September 2026.
Which products and versions are affected?: Tenda HG10 HG7_HG9_HG10re_300001138.
Is there a fix for CVE-2026-85109?: 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-2026-85109 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-85109?: Check whether you run Tenda HG10 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

A buffer overflow vulnerability exists in the Boa Web Server's formLogin function (/boaform/formLogin) within the Tenda HG10 router. The vulnerability arises from unsafe handling of the username parameter, which is copied into a fixed-size buffer using strcpy() without length validation. An attacker can craft an HTTP POST request to /boaform/formLogin with an oversized username parameter, causing a stack buffer overflow. No authentication is required; the attack is remotely exploitable over the network. Exploitation has been demonstrated to cause denial-of-service (device crash), and depending on memory layout and runtime protections, could potentially enable arbitrary code execution. The vulnerability affects firmware version 300001138 and has been publicly disclosed with proof-of-concept code available.

Affected products

Tenda HG10 HG7_HG9_HG10re_300001138

Timeline

2026-09-03: disclosed: Publicly disclosed via GitHub and NVD
2026-09-03: other: CVE-2026-85109 assigned

References

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