CVE-2026-31267

Authenticated router crash via administrative request overflow

Published Jul 9, 2026 · Updated Jul 9, 2026

Stack buffer overflow in the Mercusys MW302R administrative interface allows remote authenticated users to crash firmware 1.4.10 Build 231023. The disclosure does not name the request handler or input field, but states that crafted request data overwrites a stack buffer and redirects control flow to an arbitrary instruction address. Exploitation requires administrative authentication and adjacent-network access; the documented consequence is a system crash, with no confidentiality or integrity impact reported.

CVSS severity5.7
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in the Mercusys MW302R administrative interface allows remote authenticated users to crash firmware 1.4.10 Build 231023. The disclosure does not name the request handler or input field, but states that crafted request data overwrites a stack buffer and redirects control flow to an arbitrary instruction address. Exploitation requires administrative authentication and adjacent-network access; the documented consequence is a system crash, with no confidentiality or integrity impact reported.

The record

CVE
CVE-2026-31267
Published
Jul 9, 2026
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-121, T1499
Attack vector
adjacent
Privileges
admin

Timeline

How it unfolded

  1. Jul 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record 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 vectoradjacent
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.7CISA-ADPCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1499Endpoint Denial of Service

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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