CVE-2025-20738

Local privilege escalation via stack overflow

Published Nov 4, 2025 · Updated Nov 4, 2025

Stack overflow in MediaTek's WLAN AP driver on SDK 7.6.7.2 and earlier or OpenWRT 19.07 and 21.02 allows local users to escalate privileges. The driver uses an incorrect bounds check before a write, allowing the destination stack buffer to be overrun; MediaTek has not named the affected routine or input. Exploitation requires existing System privilege and no user interaction; the disclosed consequence is elevation beyond the existing System context.

CVSS severity6.7
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack overflow in MediaTek's WLAN AP driver on SDK 7.6.7.2 and earlier or OpenWRT 19.07 and 21.02 allows local users to escalate privileges. The driver uses an incorrect bounds check before a write, allowing the destination stack buffer to be overrun; MediaTek has not named the affected routine or input. Exploitation requires existing System privilege and no user interaction; the disclosed consequence is elevation beyond the existing System context.

The record

CVE
CVE-2025-20738
Published
Nov 4, 2025
Updated
Nov 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-121, CWE-787, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Nov 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.7CISA-ADPCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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