CVE-2026-20403 Denial of service in MediaTek chipset
A missing bounds check in MediaTek modem firmware allows remote attackers to cause a system crash via a rogue base station.
- 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-2026-20403?
CVE-2026-20403 is a medium-severity denial of service vulnerability in Mediatek Nr15, published on 2 Feb 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 system crash due to a missing bounds check. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01689254 (Note: For N15 and NR16) / MOLY01689259 (Note: For NR17 and NR17R); Issue ID: MSV-4843.
Weakness: CWE-787
Which versions are affected by CVE-2026-20403?
It affects 4 products.
Products include Mediatek Nr15, Mediatek Nr16, Mediatek Nr17, Mediatek Nr17r.
How do I fix CVE-2026-20403?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-20403 being exploited?
There is no known exploitation of CVE-2026-20403 in the wild and no public exploit code.
Other vulnerabilities in Mediatek Nr15
- CVE-2024-20082 Memory corruption in MT2735, MT2737, MT6833, MT6835, MT6835T, MT6853, MT6855, MT6873, MT6875, MT6875T, MT6877, MT6879, MT6880, MT6883, MT6885, MT6886, MT6889, MT6890, MT6891, MT6893, MT6895, MT6895T, MT6896, MT6897, MT6980, MT6980D, MT6983, MT6985, MT6989, MT6990
- CVE-2025-20708 Memory corruption in MT2735, MT2737, MT6813, MT6815, MT6833, MT6833P, MT6835, MT6835T, MT6853, MT6853T, MT6855, MT6855T, MT6873, MT6875, MT6875T, MT6877, MT6877T, MT6877TT, MT6878, MT6878M, MT6879, MT6880, MT6883, MT6885, MT6886, MT6889, MT6890, MT6891, MT6893, MT6895, MT6895TT, MT6896, MT6897, MT6899, MT6980, MT6980D, MT6983, MT6983T, MT6985, MT6985T, MT6989, MT6989T, MT6990, MT6991, MT8673, MT8675, MT8676, MT8678, MT8771, MT8791, MT8791T, MT8792, MT8795T, MT8797, MT8798, MT8863, MT8873, MT8883, MT8893
- CVE-2024-20094 Denial of service in MT2735, MT6833, MT6853, MT6855, MT6873, MT6875, MT6875T, MT6877, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT8675, MT8771, MT8791, MT8791T, MT8797
- CVE-2024-20003 Denial of service in MT2735, MT6297, MT6833, MT6853, MT6855, MT6873, MT6875, MT6875T, MT6877, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT8675, MT8791, MT8791T, MT8797
- CVE-2024-20004 Denial of service in MT2735, MT6297, MT6833, MT6853, MT6855, MT6873, MT6875, MT6875T, MT6877, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT8675, MT8791, MT8791T, MT8797
Sources
Also known as GHSA-2rrf-rvr2-f97v.