What is the CVSS score of CVE-2026-21389?

CVE-2026-21389 has a CVSS 3.1 base score of 8.0 (High). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of Xweb 500d Pro Firmware are affected by CVE-2026-21389?

A high-severity remote code execution vulnerability in XWEB Pro 1.12.1 and earlier allows authenticated users to execute arbitrary commands on affected systems through the contacts import function.

How to fix or mitigate CVE-2026-21389?

Within 24 hours: Identify all systems running XWEB Pro 1.12.1 or earlier and restrict access to the contacts import feature through network controls or user privilege management. Within 7 days: Implement compensating controls such as WAF rules to block malicious payloads to the import endpoint, and enable enhanced logging/monitoring of import activities. Within 30 days: Upgrade to a patched version once available, or plan for alternative software deployment if patches are not forthcoming from the vendor.

Xweb 500d Pro Firmware CVE-2026-21389

HIGH

OS Command Injection (CWE-78)

2026-02-27 ics-cert@hq.dhs.gov

RCE Command Injection Xweb 500d Pro Firmware Xweb 300d Pro Firmware Xweb 500b Pro Firmware

8.0

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.0 HIGH

AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

High

Privileges Required

High

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

CVE Published

Feb 27, 2026 - 01:16 nvd

HIGH 8.0

DescriptionCVE.org

An OS command injection vulnerability exists in XWEB Pro version 1.12.1 and prior, enabling an authenticated attacker to achieve remote code execution on the system by injecting malicious input into the request body sent to the contacts import route.

AnalysisAI

Remote code execution in XWEB Pro firmware (versions 1.12.1 and earlier) allows authenticated attackers to execute arbitrary OS commands by submitting malicious input through the contacts import endpoint. The vulnerability affects multiple Xweb Pro models (500d, 300d, and 500b) and requires high-level privileges but can compromise the entire system. No patch is currently available.

Technical ContextAI

Classified as CWE-78 (OS Command Injection). Affects Xweb 300D Pro Firmware. An OS command injection vulnerability exists in XWEB Pro version 1.12.1 and prior, enabling an authenticated attacker to achieve remote code execution on the system by injecting malicious input into the request body sent to the contacts import route.