Critical severity · published Oct 12, 2026
CVE-2026-66086
Stack-based Buffer Overflow in Modem
9.8
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
Modem · Unisoc (Shanghai) Technologies Co., Ltd.
T8100; T9100; UDX710 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-66086
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-66086
www.unisoc.com
https://www.unisoc.com/en/support/product-security-bulletin/2109454821805424641
More from Modem
5.5
CVE-2026-66085
Information Disclosure in Modem