What is the CVSS score of CVE-2025-7403?

CVE-2025-7403 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.0%.

How to fix or mitigate CVE-2025-7403?

Within 30 days: Identify all affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.

Zephyr CVE-2025-7403

MEDIUM

Write-what-where Condition (CWE-123)

2025-09-19 vulnerabilities@zephyrproject.org

Buffer Overflow Zephyr Zephyrproject

6.5

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-123 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Write-what-where prevention
Impact	CVSS score of 7.6 (HIGH). Attack characteristics: adjacent network attack vector, low complexity, no privileges required, no user interaction not required. EPSS exploitation probability: 0.02%.
Exploit ScenarioDerived	Successful exploitation could compromise the high-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

Unsafe handling in bt_conn_tx_processor causes a use-after-free, resulting in a write-before-zero. Rated high severity (CVSS 7.6), this vulnerability is no authentication required, low attack complexity.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-123. Unsafe handling in bt_conn_tx_processor causes a use-after-free, resulting in a write-before-zero. The written 4 bytes are attacker-controlled, enabling precise memory corruption. Affected products include: Zephyrproject Zephyr.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.5 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Severity Changed

Oct 13, 2026 - 20:23 NVD

HIGH MEDIUM

CVSS changed

Oct 13, 2026 - 20:23 NVD

7.6 (HIGH) 6.5 (MEDIUM)

Patch released

Mar 28, 2026 - 19:13 nvd

Patch available

CVE Published

Sep 19, 2025 - 06:15 nvd

HIGH 7.6

DescriptionNVD

Unsafe handling in bt_conn_tx_processor causes a use-after-free, resulting in a write-before-zero. The written 4 bytes are attacker-controlled, enabling precise memory corruption.

Executive ViewAI

Why It Matters

CVE-2025-7403 presents notable security risk rated CVSS 7.6. Exploitation could compromise the security of affected deployments. A patch is available and should be applied as part of regular vulnerability management.

Business Impact: High

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score

0.0%

Top 94% exploitable

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 0.0%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Controlled

Automatable· derived

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +32

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.