CVE-2026-20419

7.5 HIGH
Denial of Service

📋 TL;DR

This vulnerability in MediaTek wlan AP/STA firmware allows remote attackers within wireless range to cause denial of service by making the system unresponsive. The flaw requires no user interaction or special privileges to exploit, affecting devices using vulnerable MediaTek wireless chipsets.

💻 Affected Systems

Products:
  • MediaTek wlan AP/STA firmware
Versions: Specific versions not detailed in bulletin; affected versions prior to patches WCNCR00461663/WCNCR00463309
Operating Systems: Embedded systems using MediaTek wireless chipsets
Default Config Vulnerable: ⚠️ Yes
Notes: Affects devices with MediaTek wireless hardware in AP or STA modes; exact device models not specified in available information.

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system lockup requiring physical power cycle, disrupting all wireless connectivity and potentially affecting device functionality.

🟠

Likely Case

Temporary wireless connectivity loss affecting network-dependent services until system recovers or reboots.

🟢

If Mitigated

Minimal impact with proper network segmentation and wireless security controls limiting attack surface.

🌐 Internet-Facing: MEDIUM - Requires attacker to be within wireless range, but no authentication needed.
🏢 Internal Only: HIGH - Internal attackers can easily exploit from adjacent network segments.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ⚠️ Yes
Complexity: LOW

Exploitation requires sending specially crafted wireless packets; no authentication needed.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patches WCNCR00461663 and WCNCR00463309

Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/February-2026

Restart Required: Yes

Instructions:

1. Check device manufacturer for firmware updates. 2. Apply MediaTek patches WCNCR00461663 or WCNCR00463309. 3. Reboot device after patching. 4. Verify patch installation.

🔧 Temporary Workarounds

Wireless Network Segmentation

all

Isolate vulnerable devices on separate wireless networks with strict access controls.

MAC Address Filtering

all

Implement MAC address whitelisting to restrict which devices can connect to vulnerable APs.

🧯 If You Can't Patch

  • Segment vulnerable devices on isolated network segments
  • Implement wireless intrusion detection/prevention systems

🔍 How to Verify

Check if Vulnerable:

Check firmware version against vendor advisory; devices with MediaTek wireless chipsets without patches WCNCR00461663/WCNCR00463309 are vulnerable.

Check Version:

Device-specific; typically through device management interface or manufacturer tools.

Verify Fix Applied:

Verify firmware version includes patches WCNCR00461663 or WCNCR00463309; test wireless functionality under load.

📡 Detection & Monitoring

Log Indicators:

  • Unexpected system reboots
  • Wireless interface errors
  • System unresponsive events

Network Indicators:

  • Unusual wireless packet patterns
  • Multiple connection attempts to same AP

SIEM Query:

Wireless logs showing repeated connection failures OR system logs with 'unresponsive' events near wireless activity

📊 Metadata

CVE ID: CVE-2026-20419
CVSS v3 Score: 7.5 (HIGH)
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-754
Published: February 2, 2026
Last Updated: February 4, 2026

🤖 AI-assisted analysis, reviewed for accuracy

🔗 References

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