VulnerabilityPublished 4 Nov 2025Updated 26 Feb 2026

CVE-2025-20734: MediaTek MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, MT7986 · Heap Overflow

Affects MediaTek MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, MT7986Source CVE Database V5

Not known to be exploited · CVSS 4.2 Medium : upgrade to 19.07 when convenient.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score

4.2Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 19.07

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade MediaTek MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, MT7986 to 19.07.

Affected software

Product	Affected	Fixed in
MediaTek, Inc. MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, MT7986	Affected <19.07 =21.02	Fixed in 19.07

AI-suggested

To mitigate CVE-2025-20734, organizations should promptly apply the vendor-provided patch identified as WCNCR00441507 to all affected MediaTek chipsets and devices running SDK release 7.6.7.2 or earlier and openWRT versions 19.07 and 21.02. Network administrators should audit existing devices to identify those using vulnerable MediaTek WLAN AP drivers. Where patching is not immediately possible, consider isolating affected devices on segmented networks with strict access controls to limit local privilege escalation opportunities. Employ strict access management to prevent unauthorized users from obtaining System-level privileges, as exploitation requires such access. Regularly monitor device logs and network traffic for unusual activity indicative of exploitation attempts. Additionally, maintain up-to-date firmware and software inventories and integrate vulnerability scanning focused on embedded network devices. Collaborate with vendors and suppliers to ensure timely updates and security advisories are received and acted upon.

Description

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: WCNCR00441507; Issue ID: MSV-4112.

Impact

The primary impact of CVE-2025-20734 is local privilege escalation on devices using affected MediaTek WLAN AP drivers. An attacker with existing System privileges could exploit this heap overflow to gain higher privileges, potentially allowing them to execute arbitrary code with elevated rights, manipulate system processes, or disrupt device operation. This could lead to compromised confidentiality, integrity, and availability of the device and the network it supports. In enterprise environments, this could facilitate lateral movement or persistence within internal networks. Although exploitation requires prior System-level access, the vulnerability increases the risk profile of affected devices by enabling privilege escalation without user interaction. Given the widespread use of MediaTek chipsets in wireless access points and routers, the vulnerability could affect a broad range of consumer, SMB, and enterprise network devices globally, potentially impacting network security and stability.

CWE-122Heap-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #16
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
Pre-design: Use a language or compiler that performs automatic bounds checking.
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Forced Integer Overflow (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

corp.mediatek.com/product-security-bulletin/November-2025 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Feb 2026, 00:36 UTC

WeaknessesCWE-122

Technical details

References

Community reviews

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