CVE-2026-20434 Memory corruption in MediaTek chipset

High 7.5 Published Updated

A missing bounds check in MediaTek modem firmware allows remote privilege escalation via a rogue base station, requiring user interaction.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Local or same network only
Victim action needed
Not needed
Fix
Available

What is CVE-2026-20434?

CVE-2026-20434 is a high-severity memory corruption vulnerability in Mediatek Nr15, published on 2 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In Modem, there is a possible out of bounds write due to a missing bounds check. This could lead to remote escalation of privilege, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is needed for exploitation. Patch ID: MOLY00782946; Issue ID: MSV-4135.

Weakness: CWE-787

Which versions are affected by CVE-2026-20434?

It affects 5 products.

Products include Mediatek Lr12a, Mediatek Lr13, Mediatek Nr15, Mediatek Nr16, Mediatek Nr17.

How do I fix CVE-2026-20434?

Apply the vendor's patch.

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

Is CVE-2026-20434 being exploited?

There is no known exploitation of CVE-2026-20434 in the wild and no public exploit code.

All Mediatek Nr15 vulnerabilities

Sources

Also known as A-473385376, ASB-A-473385376, GHSA-q532-r27c-r7m9, M-MOLY00782946.

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