CVE-2026-40003
MediumWhat is CVE-2026-40003?
ZTE ZX297520V3 BootROM contains a vulnerability that allows arbitrary memory writes via USB. Attackers can exploit the lack of target address validation in the USB download mode to write data to any location in BootROM runtime memory, thereby overwriting the stack, hijacking the execution flow, bypassing the Secure Boot signature verification mechanism, and achieving unauthorized code execution.
CVSS Vector Breakdown
CVSS 3.1Requires physical presence — attacker must physically touch the device (e.g. USB port).
Exploit requires specific conditions, timing, or configuration to succeed.
No authentication required. Any anonymous user can exploit this vulnerability.
Victim must take an action (e.g. click a link, open a file) for the exploit to succeed.
Exploiting the vulnerability only affects the vulnerable component itself.
Some sensitive information is disclosed, but attacker has limited access.
Complete loss of integrity. Attacker can modify any file or data on the component.
Reduced performance or intermittent outages, but service remains available.
FAQ
CVE-2026-40003 has a CVSS score of 5.1/10, rated as Medium. Review the affected products list and apply vendor patches.
CVSS (Common Vulnerability Scoring System) rates vulnerability severity from 0.0 to 10.0. CVE-2026-40003 scores 5.1/10 (Medium). Scores 9.0–10.0 are Critical, 7.0–8.9 are High, 4.0–6.9 are Medium, and below 4.0 are Low.
The list of devices confirmed to be affected by CVE-2026-40003 is shown in the "Affected Devices" section above. Check your firmware version against the vendor security advisory and apply the latest patch.
Apply the latest firmware or software update from the vendor. Check the References section above for official advisories and patch notes. If no patch is available, consider disabling the affected feature or isolating the device from untrusted networks.