CVE-2026-40003: ZTE ZX297520V3 BootROM contains a vulnerability that allows arbitrary memory writes via USB

Routine

MEDIUM 5.1MITIGATE

CVE-2026-40003 is a medium-severity flaw (CVSS 5.1) affecting zx297520v3 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.1 (Medium)
Attack vector	Physical
Attack complexity	High
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 78%)
CISA exploited list	No
Weakness	CWE-787
Published	2026-05-07
Last modified	2026-10-26

Publisher (CNA): ZTE Corporation · Vendor: zte

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-07 02:16 UTCPublished CVE record published
2026-10-26 19:10 UTCUpdated Record last modified

zte zx297520v3 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40003?

zx297520v3 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-40003 being exploited?

CVE-2026-40003 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40003 affect?

CVE-2026-40003 affects zx297520v3 firmware. Severity is medium (CVSS 5.1). 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, there

How urgent is CVE-2026-40003?

Priority 23/100. No elevated risk signals yet.

Software pages

ZTE vulnerabilities

References

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