CVE-2026-21548 Denial of service in T8100/T9100/T8200/T8300
Remote attackers with system privileges can cause denial of service in Unisoc modem firmware due to improper input validation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-21548?
CVE-2026-21548 is a high-severity denial of service vulnerability in Unisoc (Shanghai) Technologies Co., Ltd. T8100/T9100/T8200/T8300, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In nr modem, there is a possible improper input validation. This could lead to remote denial of service with System execution privileges needed.
Weakness: CWE-20
Which versions are affected by CVE-2026-21548?
How do I fix CVE-2026-21548?
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-2026-21548 being exploited?
There is no known exploitation of CVE-2026-21548 in the wild and no public exploit code.
Sources
Also known as A-517353300, ASB-A-517353300, GHSA-g497-jcg3-rfwj, U-3293610.