Unisoc Modem: Stack-based buffer overflow in OTA stack
Summary
A stack-based buffer overflow in the modem OTA stack of certain Unisoc chipsets allows an attacker to trigger remote code execution or denial of service. The flaw is caused by improper validation of scheduling information in SIB1 messages. According to the CVE record, no additional execution privileges are needed, but the research notes indicate that exploitation likely requires radio proximity to the device, such as a rogue base station, which is not confirmed by the vendor.
Affected
- Unisoc modem chipsets T8100, T9100 and UDX710 (named in the CVE record and aggregators)
- Affected firmware or build versions: Unknown.
- Devices with these basebands, such as budget Android phones, tablets, cellular routers or IoT modules, depend on the device vendor.
Fixed in
Unknown. No fixed version or patch has been confirmed in the sources reviewed.
Workaround
No vendor workaround documented. Generic advice from a non-primary blog is to avoid high-risk locations and minimise cell usage near suspicious cellular base stations; this is not a fix.
Exploitation
- CISA KEV: not listed.
- Exploited in the wild: no evidence found.
- Public PoC: one aggregator reports none detected; not verified.
- EPSS: 0.00455 (low).
- CISA SSVC: Automatable yes, Technical Impact total, Exploitation none.
Our recommendation
- Inventory devices, modules and routers that use Unisoc basebands (T8100, T9100, UDX710).
- Ask device and module vendors for their Unisoc baseband fix status and apply firmware updates as soon as they are available.
- Check the Unisoc security bulletin regularly for patched modem versions.
- Prioritise mobile fleets with Unisoc devices; treat other business systems as low exposure.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Unisoc Security Bulletin www.unisoc.com
- OpenCVE CVE-2026-66086 app.opencve.io
- Vulners RAPID7 CVE-2026-66086 vulners.com
- HOL Guard CVE-2026-66086 hol.org
- Threatint CVE-2026-66086 cve.threatint.com
- Strix CVE-2026-66086 www.strix.ai
- TheHackerWire CVE-2026-66086 www.thehackerwire.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 30 Oct 2026, 19:14.
Original description (NVD)
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.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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