CVE-2021-31698
CVSS 9.8 CRITICAL: quectel EG25-G devices through 202006130814 allow executing arbitrary code remotely by using an AT command to place… EPSS 2% (80th percentile).
Vulnerabilities & Exploits · IoT / OT Attack
Researchers from the University of Birmingham and Fuzzware showed that a hostile SIM card could trigger modem commands on cellular IoT gear, with tests finding the feature active in 9 of 26 phones and modules and a live demonstration on a commercial EV charger.
The trick is that the SIM can send a proactive RUN AT command back into the modem, asking it to run AT commands, the control language modems use for their own management. On Quectel-built modules and some Qualcomm-based devices, that gives the card a local console inside the radio stack, so a physical SIM swap or interposer can reach code execution without touching the network first.
That shifts the trust boundary for machine-to-machine fleets: if the SIM tray is accessible, the attack path sits below remote defenses and can survive even when the device is otherwise isolated. The paper says five of the six affected modules were Quectel parts, including units pulled from an EV charger, an industrial router, and a telematics control unit.
2 sources · Aug 11
CVSS 9.8 CRITICAL: quectel EG25-G devices through 202006130814 allow executing arbitrary code remotely by using an AT command to place… EPSS 2% (80th percentile).
CVSS 6.8 MEDIUM: in processLaunchBrowser of CommandParamsFactory.java, there is a possible browser interaction from the lockscreen due to improper locking. EPSS 0.2% (5th percentile).
Help Net Security
Malicious SIMs can hijack smartphones, steal files, and lock them onto 2G - Help Net Security
Malicious SIM cards can send commands to phones, EV chargers, and IoT devices, enabling data theft, 2G downgrades, and code execution.
originalThe Hacker News
A Malicious SIM Card Can Run Attacker Code Inside the Modems Behind Cellular IoT Devices
Malicious SIM cards can use RUN AT to execute modem commands on cellular IoT devices, including EV chargers, routers, and telematics units.
originalPart of the PlainSec briefing for 2026-08-11
Every edition of this story: Hostile SIMs Gain Control of Quectel Modems