Zyxel security advisory for FragAttacks against Wi-Fi products

CVE: CVE-2020-26139, CVE-2020-26140, CVE-2020-26141, CVE-2020-26142, CVE-2020-26143, CVE-2020-26144, CVE-2020-26145, CVE-2020-26146, CVE-2020-26147, CVE-2020-24586, CVE-2020-24587, CVE-2020-24588


Zyxel is aware of the FRagmentation and AGgregation Attacks against Wi-Fi vulnerability (dubbed “FragAttacks”) and is releasing patches for some vulnerable Wi-Fi products. Customers are advised to adopt the applicable firmware updates or follow the advice below for optimal protection.


What's the vulnerability?

The FragAttack vulnerability was identified in the IEEE 802.11 implementation of de-aggregation and de-fragmentation of frames at the receiver in some Wi-Fi devices. There are twelve CVEs reported by Wi-Fi Alliance®, namely:

  • CVE-2020-26139: Forwarding EAPOL frames even though the sender is not yet authenticated (should only affect APs).
  • CVE-2020-26140: Accepting plaintext data frames in a protected network.
  • CVE-2020-26141: Not verifying the TKIP MIC of fragmented frames.
  • CVE-2020-26142: Processing fragmented frames as full frames.
  • CVE-2020-26143: Accepting fragmented plaintext data frames in a protected network.
  • CVE-2020-26144: Accepting plaintext A-MSDU frames that start with an RFC1042 header with EtherType EAPOL (in an encrypted network).
  • CVE-2020-26145: Accepting plaintext broadcast fragments as full frames (in an encrypted network).
  • CVE-2020-26146: Reassembling encrypted fragments with non-consecutive packet numbers.
  • CVE-2020-26147: Reassembling mixed encrypted/plaintext fragments.
  • CVE-2020-24586: Not clearing fragments from memory when (re)connecting to a network
  • CVE-2020-24587: Reassembling fragments encrypted under different keys
  • CVE-2020-24588: Accepting non-SPP A-MSDU frames

Please refer to the official CVEs for the technical details and severity.

It is important to note that exploiting these weaknesses is not a trivial task. Specifically, an attacker has to be physically within the wireless range of the vulnerable device, obtain a man-in-the-middle position, and entice user interaction to get the user to click or visit a compromised website. According to Wi-Fi Alliance®, there is currently no evidence of the vulnerabilities being used maliciously against Wi-Fi users.


What versions are vulnerable—and what should you do?

After a thorough investigation, we’ve identified the affected products that are within their warranty and support period, as shown in the table below. We are already working with Wi-Fi chip vendors to prepare the patches and will continue to update the advisory as additional information becomes available. We encourage customers to install the applicable updates when available for optimal protection.

Please note that the table does NOT include customized models for internet service providers (ISPs).

Affected series/modelsPatch available in
LTE3202-M430Patch not supported. Please follow the general security practices
LTE3202-M437To be updated
LTE3301-M209Patch not supported. Please follow the general security practices
LTE3302-M432Patch not supported. Please follow the general security practices
LTE3316-M604(v1)Patch not supported. Please follow the general security practices
LTE3316-M604(v2)To be updated
LTE4506-M606Patch not supported. Please follow the general security practices
LTE5366Patch not supported. Please follow the general security practices
LTE5388-M804V1.00(ABSQ.2)C0 in Apr. 2022*
LTE5388-S905V1.00(ABVI.5)C0 in Q4 2021*
LTE7240-M403V2.00(ABMG.4)C0 in Dec. 2021
LTE7461-M602V2.00(ABQN.4)C0 in Q4 2021*
LTE7480-M804V1.00(ABRA.3)C0 in Dec. 2021
LTE7480-S905V2.00(ABQT.5)C0 in Q4 2021*
LTE7485-S905V1.00(ABVN.5)C0 in Q4 2021*
LTE7490-M904V1.00(ABQY.3)C0 in Apr. 2022*
NR2101V1.00(ABUS.4)C0 in Apr. 2022*
NR5101V1.00(ABVC.3)C0 in Q4 2021*
NR7101V1.00(ABUV.4)C0 in Q4 2021*
WAH7601To be updated
WAH7608To be updated
WAH7706Patch not supported. Please follow the general security practices
DX4510-B0V5.17(ABYL.0)C0 in Q2 2021*
DX3301-T0V5.50(ABVY.1)C0 in Q3 2021*
DX5401-B0V5.17(ABYO.1)C0 in Dec. 2021*
EMG1702-T10AV1.00(ABNZ.1)C0 in Q4 2021*
EMG3425-Q10APatch not supported. Please follow the general security practices
EMG3524-T10AV5.41(ABXU.1)C0 in Q3 2021*
EMG3525-T50BEMEA: V5.50(ABPM.6)C0 in Dec. 2021*
S. America: V5.50(ABSL.0)C0 in Q3 2021*
EMG5523-T50BEMEA: V5.50(ABPM.6)C0 in Dec. 2021*
S. America: V5.50(ABSL.0)C0 in Q3 2021*
EMG5723-T50KV5.50(ABOM.7)C0 in Dec. 2021*
EMG6726-B10AV5.13(ABNP.6)C0 in Q3 2021*
EMG8726-B50AV5.13(ABNP.6)C0 in Q3 2021*
EX3301-T0V5.50(ABVY.1)C0 in Q3 2021*
EX3510-B0V5.17(ABUP.3)C0 in Mar 2021*
EX5401-B0V5.17(ABYO.1)C0 in Dec. 2021*
EX5501-B0V5.15(ABRY.2)C0 in Dec. 2021*
EX5510-B0V5.15(ABQX.5)C0 in Q4 2021*
P-660HN-51Patch not supported. Please follow the general security practices
VMG1312-T20BV5.50(ABSB.5)C0 in Q3 2021*
VMG3625-T50BV5.50(ABPM.6)C0 in Dec. 2021*
VMG3927-B50A_B60AV5.17(ABMT.6)C0 in Dec. 2021*
VMG3927-B50BV5.13(ABLY.6)C0 in Q3 2021*
VMG3927-T50KV5.50(ABOM.7)C0 in Dec. 2021*
VMG4927-B50AV5.13(ABLY.6)C0 in Q3 2021*
VMG8623-T50BV5.50(ABPM.6)C0 in Dec. 2021*
VMG8825-B50A_B60AV5.17(ABMT.6)C0 in Q3 2021*
VMG8825-Bx0BV5.17(ABNY.7)C0 in June 2021*
VMG8825-T50KV5.50(ABOM.7)C0 in Dec. 2021*
VMG9827-B50AV5.13(ABLY.6)C0 in Q3 2021*
XMG3927-B50AV5.17(ABMT.6)C0 in Q3 2021*
XMG8825-B50AV5.17(ABMT.6)C0 in Q3 2021*
AX7501-B0V5.17(ABPC.1)C0 in Dec. 2021*
PMG5317-T20BV5.40(ABKI.4) in Mar. 2022*
PMG5617GAV5.40(ABNA.2) in Mar. 2022*
PMG5622GAV5.40(ABNB.2) in Mar. 2022*
PMG5705-T10APatch not supported. Please follow the general security practices
Wireless extenders
WAP6804Patch not supported. Please follow the general security practices
WAP6807V.100(ABTB.2)b20_C0 in Feb. 2022*
WX3310-B0V1.00(ABSF.2)C0 in Mar. 2021*
WX3100-T0V5.50(ABVL.0)C0 in Q3 2021*
WX3401-B0V5.17(ABVE.1)C0 Q3 2021*
*Please reach out to your local Zyxel support team for the file.
**The above list did not include products designed by our affiliate, Zyxel Networks. If you have questions regarding products that are not listed above, please visit here for the complete affected model list and the latest firmware release schedule.


For those vulnerable products with chips and drivers no longer supported by Wi-Fi chip vendors, we recommend that customers take the following general security practices or upgrade their devices to a patched model.

  1. Always use HTTPS to connect to websites and be aware of suspicious links.
  2. Do not connect to unprotected public Wi-Fi networks.
  3. Use strong, unique connection passwords for every service set identifier (SSID) and change them regularly.
  4. Enable WPA3-Enterprise to protect your Wi-Fi network, if supported.
  5. Use EAP-TLS, PEAP, or TTLS to authenticate a user’s identity, if supported.
  6. Enable firewall rules on the affected device or its connected gateway/firewall, if any.


Got a question or a tipoff?

If you are an ISP with customized models, please contact your Zyxel sales or service representative for further information or assistance. For end-user who acquired your Zyxel device from an ISP, please reach out to the ISP’s support team directly, as the device may have custom-built settings.


Revision history

2021-5-12: Initial release

2021-5-17: Updated the vulnerability description, general security practices, and the patch plan of CPE

2021-6-11: Updated the vulnerability description and the affected model list and patch plan of CPE and wireless extenders

2021-8-19: Updated the patch plan of ONTs

2021-11-09: Updated the patch plan of ONTs, CPE, and wireless extenders

2022-3-4: Updated the patch plan of 5G NR/4G LTE CPE and corrected the affected model list