CVE-2026-40003: zx297520v3 Memory Corruption — Fix

Description

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.

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CVSS v3.1 Score

5.1

MEDIUM

CVSS:3.1/AV:P/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
zte	zx297520v3_firmware	All
zte	zx297520v3	All

References

Advisories & Patches

https://support.zte.com.cn/zte-iccp-isupport-webui/bulletin/detail/2144487415169560645

Frequently Asked Questions

What 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. It has a CVSS v3.1 base score of 5.1 (MEDIUM).

How severe is CVE-2026-40003? +

CVE-2026-40003 has a CVSS v3.1 score of 5.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-40003? +

CVE-2026-40003 affects products from zte, specifically: zx297520v3, zx297520v3_firmware. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-40003? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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