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 300d 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 300d Pro Firmware CVE-2026-21389

HIGH

OS Command Injection (CWE-78)

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

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

Unlock full vulnerability intelligence

Risk assessment & exploitation conditions
Attack chain visualization
Remediation with exact patch versions
Threat intelligence from 22 sources
Personal watchlist & email alerts

Continue with Google Continue with GitHub

Free forever · No credit card required

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access

Authenticate to XWEB Pro

Exploit

Access contacts import route

Execution

Inject OS command in request body

Impact

Execute arbitrary system commands

Access

Authenticate to XWEB Pro

Exploit

Access contacts import route

Execution

Inject OS command in request body

Impact

Execute arbitrary system commands

Vulnerability AssessmentAI

Exploitation	Authenticated user account on XWEB Pro version 1.12.1 or earlier; access to contacts import functionality; ability to craft malicious request body with command injection payload. Additional conditions and limiting factors are described in the full assessment.
Risk Assessment	CVSS 8.0 (HIGH). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	A remote attacker (requires authentication) could exploit this vulnerability to compromise the affected system.
Remediation	Monitor vendor advisories for a patch. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

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. …

Threat intelligence, references, and detailed analysis are available after sign-in.