CVE-2026-4903 Tenda AC5 POST Request QuickIndex formQuickIndex memory corruption

High 8.7 Published 26 Mar 2026 Updated 27 Mar 2026

Remote attackers can trigger a stack-based buffer overflow in the Tenda AC5 router via a crafted POST request, potentially leading to code execution or service disruption.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-4903?

CVE-2026-4903 is a high-severity memory corruption vulnerability in Tenda AC5, published on 26 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

A flaw has been found in Tenda AC5 15.03.06.47. This vulnerability affects the function formQuickIndex of the file /goform/QuickIndex of the component POST Request Handler. This manipulation of the argument PPPOEPassword causes stack-based buffer overflow. The attack may be initiated remotely. The exploit has been published and may be used.

Weakness: CWE-121, CWE-787, CWE-119

Which versions are affected by CVE-2026-4903?

It affects 1 product.

Products include Tenda Ac5 Firmware.

How do I fix CVE-2026-4903?

No fix has been published for CVE-2026-4903 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-4903 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4903 exists.

Sources

Also known as GHSA-39fw-r4pr-87rj.