CVE-2026-66086 Stack-based Buffer Overflow in Modem
A stack-based buffer overflow in Unisoc modem firmware allows remote attackers to execute arbitrary code or cause denial of service via malicious SIB1 messages.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66086?
CVE-2026-66086 is a high-severity memory corruption vulnerability in Unisoc (Shanghai) Technologies Co., Ltd. Modem, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the modem OTA stack, there is a possible stack-based buffer overflow due to improper validation of scheduling information in SIB1 messages. This could lead to remote code execution or denial of service with no additional execution privileges needed.
Weakness: CWE-121
Which versions are affected by CVE-2026-66086?
How do I fix CVE-2026-66086?
No fix has been published for CVE-2026-66086 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-2026-66086 being exploited?
There is no known exploitation of CVE-2026-66086 in the wild and no public exploit code.
Sources
Also known as GHSA-x9v2-w4w8-7v7g.