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ASUS Router Firmware EUVDEUVD-2026-116687

| CVE-2026-84729 HIGH
Out-of-bounds Write (CWE-787)
2026-11-04 ASUS
7.2
CVSS 4.0 · Vendor: ASUS
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Attack ChainAIDerived

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

  1. Access
    Gain adjacent network access (Wi-Fi/LAN)
  2. Delivery
    Send crafted packet to router
  3. Exploit
    Trigger out-of-bounds write in firmware
  4. Execution
    Corrupt memory or crash service
  5. Impact
    Denial-of-service or integrity impact

Vulnerability Assessment

Weakness
CWE
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.

Exploitation Conditions

Exploitation requires the attacker to be on the same adjacent network as the device (AV:A - e.g., connected to the router's Wi-Fi or local LAN segment), not reachable from the general internet by default. Within that position the attack is unauthenticated (PR:N) and requires no user interaction (UI:N), achieved by sending a single crafted packet to the affected ASUS router firmware. The primary limiting factor is this adjacency requirement, which prevents mass internet-wide exploitation; additionally, only 'certain' ASUS router firmware builds are affected, so exposure depends on the specific model and firmware version in use, which the available sources do not enumerate. The available sources do not describe the exact packet or interface that triggers the out-of-bounds write.

Impact

This is a genuine but geographically-constrained risk. The CVSS 4.0 vector (AV:A/AC:L/AT:N/PR:N/UI:N) describes an adjacent-network, low-complexity, unauthenticated attack with no user interaction, and the impact is integrity and availability high (VI:H/VA:H) with no confidentiality loss (VC:N) - consistent with a CWE-787 out-of-bounds write that corrupts memory or crashes the device. The vuln.today decision label is 'this_week', indicating elevated but not emergency urgency. Key tempering signal: the attack vector is Adjacent (AV:A), not Network - the attacker must be on the same local/adjacent segment (e.g., Wi-Fi or LAN), so this is NOT internet-wide remotely exploitable against default WAN interfaces, which materially narrows the real-world exploitation surface compared to a true AV:N router flaw. No EPSS score was provided, so exploitation probability cannot be quantified. The CVE is not in CISA KEV and no working exploit is referenced, so there is no public exploit identified at time of analysis. Net: a real priority to patch (unauthenticated, low-complexity, high impact), but the adjacency requirement and absence of exploitation evidence place it below internet-facing unauthenticated RCE in triage order.

Exploit ScenarioDerived

An attacker who has gained access to the same local network as the router - for example by joining an open or compromised Wi-Fi network - sends a specially crafted packet to the device, triggering an out-of-bounds write in the vulnerable firmware. The result is either memory corruption that could be leveraged to alter device behavior or, more readily, a denial-of-service that crashes or reboots the router. No public exploit is identified at time of analysis and the exact trigger is not described in the available sources.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet

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AnalysisAIv1 – Nov 04, 2026

Out-of-bounds write in certain ASUS router firmware lets an unauthenticated attacker on the same adjacent network send a crafted packet to corrupt memory, with high integrity and availability impact as assessed (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H). Only 'certain' firmware builds are affected, and the available sources do not enumerate the exact models, firmware versions, packet type, or interface. No public exploit identified at time of analysis, and exploitation is constrained by the requirement to be on the router's Wi-Fi or local LAN segment rather than the general internet.

RemediationAI

Patch available per vendor advisory: install the model-specific firmware update referenced in the ASUS Security Advisory's 'Security Update for ASUS Router Firmware' section (https://www.asus.com/security-advisory); the supplied data does not include an exact fixed firmware version. Because exploitation requires adjacency (AV:A), reducing exposure by segmenting untrusted devices away from the router's Wi-Fi/LAN management path and isolating guest or IoT networks lowers the attack surface while the update is applied, but these are compensating controls rather than a fix. The sources do not identify a specific port, service, or packet type that can be blocked as a targeted workaround, so no precise firewall rule can be recommended from the available data.

Affected VersionsENISA

Router firmware ASUSWRT 3.0.0.4_388 series
Router firmware ASUSWRT 3.0.0.6_102 series
Router firmware ASUSWRT 3.0.0.4_386 series

Affects your stack

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

Technical ContextAI · show details

CWE-787 (out-of-bounds write) in ASUS router firmware means a crafted packet can cause data to be written past the bounds of an intended buffer, producing memory corruption that the assessed vector maps to high integrity and availability impact (I:H/A:H) with no confidentiality impact. The affected CPE is cpe:2.3:a:asus:router_firmware:*:*:*:*:*:*:*:*, which does not specify a version range in the supplied data. Attack prerequisites are adjacency (AV:A) - the attacker must be on the router's Wi-Fi or local LAN segment - with no authentication (PR:N) and no user interaction (UI:N). The trigger packet and the vulnerable parser or interface are not described in the available sources.

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Severity by source

Vendor (ASUS) PRIMARY 7.2 HIGH
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
vuln.today AI 8.1 HIGH

Adjacent crafted packet gives AV:A/AC:L and unauthenticated PR:N/UI:N; out-of-bounds write yields I:H and A:H with no data disclosure, so C:N.

3.1 AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
4.0 AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (ASUS).

CVSS VectorVendor: ASUS

Attack Vector
Adjacent
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
None
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

Out-of-bounds write in certain ASUS Router firmware allow an unauthenticated nearby attacker to write data beyond the intended buffer or potentially cause a denial-of-service (DoS) via a crafted packet. Refer to the ' Security Update for ASUS Router Firmware  ' section on the ASUS Security Advisory for more information.

Executive ViewAI

Why It Matters

A high-severity memory corruption vulnerability in certain ASUS router firmware allows an unauthenticated attacker on the same local network to disrupt and potentially manipulate router operations, affecting integrity and availability. Leadership should care because compromised routers can enable lateral movement, service outages, and loss of trust in network security, impacting both employees and customers who rely on these devices.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis; interim mitigations include isolating affected routers on separate network segments, restricting local network access to trusted devices, monitoring for anomalous traffic, and applying strict firewall rules to limit exposure.

Threat Intelligence Overview

Prevalence
High
ASUS is a major consumer/SOHO router brand with a large installed base
Social Media
1
Sightings
Data Quality
3 sources
Confidence: Low

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 N/A
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
Scheduled
Exploitation· derived
None
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact
High

Priority Score

36
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

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 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.

References

Advisories & patches

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