What is the CVSS score of CVE-2025-20715?

CVE-2025-20715 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

How to fix or mitigate CVE-2025-20715?

Within 24 hours, inventory all MediaTek SDK and OpenWrt 19.07.0/21.02.0 devices using the wlan AP driver, restrict local and high-privilege access to those devices, and open a vendor-advisory watch for Patch ID WCNCR00421152. Within 7 days, validate whether the referenced MediaTek October 2025 patch is applicable and deploy it if confirmed available; otherwise apply interim mitigations such as management-network segmentation, least-privilege enforcement, and enhanced logging for local privilege changes. Within 30 days, migrate affected devices off unsupported OpenWrt 19.07.0/21.02.0 to supported releases or vendor-supported firmware, confirm patch status with MediaTek, and conduct a risk review of any internet- or untrusted-network-exposed AP management interfaces. No vendor-released patch is identified in the provided metadata, but Patch ID WCNCR00421152 is referenced in MediaTek's October 2025 security bulletin; validate its availability before deployment.

MediaTek WLAN Driver CVE-2025-20715

HIGH

Out-of-bounds Write (CWE-787)

2025-10-14 security@mediatek.com

Privilege Escalation Buffer Overflow Memory Corruption Mediatek Openwrt Software Development Kit

7.8

CVSS 3.1 · Vendor: mediatek

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Obtain System privilege locally
Exploit

Trigger OOB write in wlan AP driver
Impact

Escalate to kernel-level privilege

Vulnerability Assessment

Weakness	CWE CWE-787 ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, write limits MITRE ATT&CK 2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	Exploitation requires local access to a device running the affected MediaTek wlan AP driver (MediaTek SDK; OpenWRT 19.07.0 and 21.02.0 among affected platforms) AND, per the description, the attacker must already hold System privilege before triggering the out-of-bounds write. No user interaction is needed. Limiting factors: this is not remotely reachable (AV:L), cannot be launched by an unprivileged or anonymous actor, and serves as a privilege-boundary escape from System to kernel rather than an initial-access vector - materially narrowing realistic risk despite the 7.8 base score.
Impact	This is a genuine but conditional local privilege-escalation issue, not an internet-facing emergency. The NVD CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, 7.8 HIGH) indicates purely local attack with low complexity and no user interaction, but the description explicitly states exploitation requires an actor who 'has already obtained the System privilege' - which is a HIGH-privilege precondition, conflicting with the vendor-assigned PR:L. This discrepancy should be verified with MediaTek; treated honestly, the real bar is high-privilege local code execution being used to cross into the kernel/driver trust boundary. All exploitation signals point to low urgency: EPSS is 0.14% (3rd percentile), there is no CISA KEV listing, and no public POC is referenced. SSVC framing would be roughly exploitation=none, automatable=no (local-only, precondition of System privilege), technical impact=total. Net: a real but lower-priority hardening fix - meaningful for defense-in-depth on affected MediaTek-based devices (sandbox/privilege-boundary escape) rather than a mass-exploitation threat. Patch ID WCNCR00421152 exists per MediaTek's October 2025 bulletin.
Exploit ScenarioDerived	An attacker who has already gained System-level privilege on a MediaTek-based device (e.g., via a prior compromise or a malicious app running as System) invokes the vulnerable wlan AP driver path with crafted input, triggering an out-of-bounds write from an incorrect bounds check. The memory corruption is leveraged to escalate from System to kernel/driver privilege. No user interaction is required, but the local System-privilege precondition and absence of any public exploit significantly limit real-world use.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.1% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Oct 08, 2026

An out-of-bounds write in MediaTek's wlan AP driver (CVE-2025-20715, CWE-787) lets a local attacker who already holds System privilege escalate to kernel-level code execution, because the driver performs an incorrect bounds check when handling data. The affected surface spans MediaTek's software development kit and OpenWrt 19.07.0 and 21.02.0 platforms that embed the driver, and exploitation requires local access plus pre-existing high privileges per our assessed vector (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H) with no user interaction. EPSS is only 0.14% (3rd percentile) and no public exploit code has been identified, so this is a conditional local privilege-boundary escape rather than an internet-facing emergency; a vendor patch (Patch ID WCNCR00421152, Issue MSV-3731) is referenced in MediaTek's October 2025 security bulletin.

RemediationAI

Apply the vendor fix identified as Patch ID WCNCR00421152, which resolves Issue MSV-3731, and consult MediaTek's October 2025 Product Security Bulletin (https://corp.mediatek.com/product-security-bulletin/October-2025) for the exact driver/firmware version containing the patch; OpenWrt users on 19.07.0 or 21.02.0 that bundle the affected driver should upgrade to vendor-released builds that incorporate the patched MediaTek driver or migrate off these end-of-life branches. Because no public exploit has been identified and EPSS is very low, patching can follow normal maintenance cadence rather than emergency change windows. Where immediate upgrade is not possible, compensating controls should target the assessed prerequisites: restrict local login and shell access so untrusted users cannot reach System privilege (the privilege level the attack requires), which shrinks the attack surface but does not eliminate risk for legitimate System-level accounts; harden or disable unused WLAN AP functionality and management interfaces where the deployment does not require them, accepting the trade-off of reduced wireless service; and enforce least privilege plus monitoring for unexpected privilege-boundary crossings from System into kernel. These controls are mitigations only and are less reliable than installing the vendor patch once the corresponding updated driver/firmware is available.

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

The flaw is a classic CWE-787 out-of-bounds write in the MediaTek wlan AP (access point) driver, root-caused to an incorrect bounds check that fails to validate a length or index before writing into a buffer, allowing memory corruption within the kernel/driver context. Because the vulnerable code lives in a wireless driver supplied through MediaTek's software development kit, the exposure propagates to downstream firmware and router distributions built on that SDK, as reflected in the CPE data (cpe:2.3:a:mediatek:software_development_kit and cpe:2.3:o:openwrt:openwrt:19.07.0 and 21.02.0). Unlike a remote over-the-air Wi-Fi attack, the assessed vector is local-only (AV:L) and requires high privileges (PR:H) - the attacker must already possess System privilege and is leveraging the driver flaw to cross into kernel execution. No user interaction (UI:N) is needed once those prerequisites are met, and the impact to confidentiality, integrity, and availability is high because kernel memory corruption can be shaped into code execution or a denial of service.

Know when Openwrt gets its next vulnerability

Watch products and get an email when something new is published
Check this CVE against your own stack and servers
Exploit and PoC references, threat intelligence from 22 sources

Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

Vendor (mediatek) PRIMARY 7.8 HIGH

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

vuln.today AI 6.7 MEDIUM

Description requires pre-existing System privilege, so PR:H (not vendor's PR:L); local driver interface gives AV:L, incorrect bounds check is reliably triggerable (AC:L), full C/I/A loss.

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

4.0 AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (mediatek).

CVSS VectorVendor: mediatek

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

In wlan AP driver, there is a possible out of bounds write due to an incorrect bounds check. This could lead to local escalation of privilege if a malicious actor has already obtained the System privilege. User interaction is not needed for exploitation. Patch ID: WCNCR00421152; Issue ID: MSV-3731.

Executive ViewAI

Why It Matters

MediaTek wlan AP driver and embedded OpenWrt 19.07.0/21.02.0 platforms are affected by a high-severity local privilege escalation that can let an attacker with existing high privileges reach kernel-level code execution. Leadership should care because compromise of these Wi-Fi AP platforms could undermine network segmentation and device integrity, though exploitation requires local access and pre-existing high privileges, and no public exploit has been identified at time of analysis.

Business Impact: Medium

Compensating Controls

No vendor-released patch identified at time of analysis; restrict local and high-privilege access, segment management interfaces, enforce least privilege, monitor for local privilege escalation, and track MediaTek advisory for Patch ID WCNCR00421152.

Threat Intelligence Overview

EPSS Score

0.1%

Top 97% exploitable

Prevalence

High

MediaTek WLAN drivers ship in a large fraction of consumer networking devices

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

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 HIGH

CISA KEV No

Public POC No

EPSS 0.1%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

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

Defer

Exploitation· derived

None

System Exposure· derived

Small

Automatable· derived

Human Impact

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +39

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Privilege Escalation HIGH

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.

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.

Memory Corruption HIGH

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.