CVE-2026-63821: wifi: rtw88: usb: fix memory leaks on USB write failures

Published Jul 19, 2026
·
Updated

In the Linux kernel, the following vulnerability has been resolved:

wifi: rtw88: usb: fix memory leaks on USB write failures

When rtwusbwriteport() fails to submit a USB Request Block (URB) (e.g., due to device disconnect or ENOMEM), the completion callback is never executed.

Currently, the driver ignores the return value of rtwusbwriteport() in rtwusbwritedata() and rtwusbtxaggskb(). Because these functions rely on the completion callback to free the socket buffers (skbs) and the transaction control block (txcb), a submission failure results in: 1. A memory leak of the allocated skb in rtwusbwritedata(). 2. A memory leak of the txcb structure and all aggregated skbs in rtwusbtxaggskb().

Fix this by checking the return value of rtwusbwriteport(). If it fails, explicitly free the skb in rtwusbwritedata(), and properly purge the txackqueue and free the txcb in rtwusbtxaggskb().

The issue was discovered in practice during device disconnect/reconnect scenarios and memory pressure conditions. Tested by verifying normal TX operation continues after the fix without regressions.

Affected Software

163 affected componentsFixes available
Linux Linux kernel
Microsoft azl3 kernel 6.6.143.1-1<6.6.150.1-1
6.6.150.1-1
ubuntu/linux-hwe-edge*
ubuntu/linux-aws-5.0*
ubuntu/linux-aws-5.3*
ubuntu/linux-azure*
ubuntu/linux-azure-5.3*
ubuntu/linux-azure-edge*
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.3*
ubuntu/linux-gke-4.15*
ubuntu/linux-gke-5.4*
ubuntu/linux-gkeop-5.4*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-oem*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.8*
ubuntu/linux-azure-5.11*
ubuntu/linux-azure-5.13*
ubuntu/linux-azure-5.8*
ubuntu/linux-azure-fde*
ubuntu/linux-gcp-5.11*
ubuntu/linux-gcp-5.13*
ubuntu/linux-gcp-5.8*
ubuntu/linux-gke*
ubuntu/linux-gke-5.15*
ubuntu/linux-gkeop*
ubuntu/linux-gkeop-5.15*
ubuntu/linux-hwe-5.11*
ubuntu/linux-hwe-5.13*
ubuntu/linux-hwe-5.8*
ubuntu/linux-intel-5.13*
ubuntu/linux-oem-5.10*
ubuntu/linux-oem-5.13*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
ubuntu/linux-riscv-5.8*
ubuntu/linux-allwinner-5.19*
ubuntu/linux-aws-5.19*
ubuntu/linux-aws-6.2*
ubuntu/linux-aws-6.5*
ubuntu/linux-aws-6.8*
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-6.8*
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-azure-fde-6.8*
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-gcp-6.8*
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-hwe-6.5*
ubuntu/linux-ibm-6.8*
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-lowlatency-hwe-5.19*
ubuntu/linux-lowlatency-hwe-6.2*
ubuntu/linux-lowlatency-hwe-6.5*
ubuntu/linux-lowlatency-hwe-6.8*
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-nvidia-6.8*
ubuntu/linux-oem-5.17*
ubuntu/linux-oem-6.0*
ubuntu/linux-oem-6.1*
ubuntu/linux-oem-6.5*
ubuntu/linux-oracle-6.5*
ubuntu/linux-oracle-6.8*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-riscv-6.8*
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-starfive-6.5*
ubuntu/linux-realtime-6.8*
ubuntu/linux<6.8.0-147.147
6.8.0-147.147
ubuntu/linux-aws<6.8.0-1067.70
6.8.0-1067.70
ubuntu/linux-aws-6.14*
ubuntu/linux-aws-6.17*
ubuntu/linux-aws-7.0<7.0.0-1012.12~24.04.1
7.0.0-1012.12~24.04.1
ubuntu/linux-azure<6.8.0-1071.79
6.8.0-1071.79
ubuntu/linux-azure-6.11*
ubuntu/linux-azure-6.14*
ubuntu/linux-azure-6.17*
ubuntu/linux-azure-7.0<7.0.0-1014.14~24.04.1
7.0.0-1014.14~24.04.1
ubuntu/linux-azure-fde<6.8.0-1069.76
6.8.0-1069.76
ubuntu/linux-azure-fde-6.14*
ubuntu/linux-azure-fde-6.17*
ubuntu/linux-azure-fde-7.0<7.0.0-1013.13~24.04.1
7.0.0-1013.13~24.04.1
ubuntu/linux-azure-nvidia*
ubuntu/linux-azure-nvidia-6.14*
ubuntu/linux-gcp<6.8.0-1071.79
6.8.0-1071.79
ubuntu/linux-gcp-6.11*
ubuntu/linux-gcp-6.14*
ubuntu/linux-gcp-7.0<7.0.0-1011.11~24.04.1
7.0.0-1011.11~24.04.1
ubuntu/linux-gke<6.8.0-1066.74
6.8.0-1066.74
ubuntu/linux-gkeop<6.8.0-1052.56
6.8.0-1052.56
ubuntu/linux-hwe-6.11*
ubuntu/linux-hwe-6.14*
ubuntu/linux-hwe-6.17*
ubuntu/linux-hwe-7.0<7.0.0-31.31~24.04.1
7.0.0-31.31~24.04.1
ubuntu/linux-ibm<6.8.0-1067.68
6.8.0-1067.68
ubuntu/linux-lowlatency<6.8.0-147.147.1
6.8.0-147.147.1
ubuntu/linux-lowlatency-hwe-6.11*
ubuntu/linux-nvidia*
ubuntu/linux-nvidia-6.11*
ubuntu/linux-nvidia-6.17*
ubuntu/linux-nvidia-7.0<7.0.0-1018.18~24.04.1
7.0.0-1018.18~24.04.1
ubuntu/linux-nvidia-lowlatency*
ubuntu/linux-nvidia-tegra*
ubuntu/linux-oem-6.11*
ubuntu/linux-oem-6.14*
ubuntu/linux-oem-6.17*
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle<6.8.0-1064.67
6.8.0-1064.67
ubuntu/linux-oracle-6.14*
ubuntu/linux-oracle-6.17*
ubuntu/linux-oracle-7.0<7.0.0-1011.11~24.04.1
7.0.0-1011.11~24.04.1
ubuntu/linux-raspi*
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-6.14*
ubuntu/linux-riscv-6.17*
ubuntu/linux-riscv-7.0<7.0.0-31.31.1~24.04.1
7.0.0-31.31.1~24.04.1
ubuntu/linux-xilinx*
ubuntu/linux-bluefield<6.8.0-1033.38
6.8.0-1033.38
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime<6.8.1-1062.63
6.8.1-1062.63
ubuntu/linux-realtime-6.14*
ubuntu/linux-realtime-6.17*
ubuntu/linux-aws-fips<6.8.0-1067.70+fips1
6.8.0-1067.70+fips1
ubuntu/linux-azure-fips<6.8.0-1071.79+fips1
6.8.0-1071.79+fips1
ubuntu/linux-fips<6.8.0-147.147+fips1
6.8.0-147.147+fips1
ubuntu/linux-gcp-fips<6.8.0-1071.79+fips1
6.8.0-1071.79+fips1
ubuntu/linux<7.0.0-31.31
7.0.0-31.31
ubuntu/linux-aws<7.0.0-1012.12
7.0.0-1012.12
ubuntu/linux-azure<7.0.0-1014.14
7.0.0-1014.14
ubuntu/linux-azure-fde<7.0.0-1013.13
7.0.0-1013.13
ubuntu/linux-gcp<7.0.0-1011.11
7.0.0-1011.11
ubuntu/linux-gke<7.0.0-1006.7
7.0.0-1006.7
ubuntu/linux-ibm<7.0.0-1013.13
7.0.0-1013.13
ubuntu/linux-nvidia<7.0.0-1018.18
7.0.0-1018.18
ubuntu/linux-nvidia-bos<7.0.0-2018.18
7.0.0-2018.18
ubuntu/linux-oem-7.0<7.0.0-1013.13
7.0.0-1013.13
ubuntu/linux-oracle<7.0.0-1011.11
7.0.0-1011.11
ubuntu/linux-raspi<7.0.0-1019.19
7.0.0-1019.19
ubuntu/linux-realtime<7.0.0-31.31.1
7.0.0-31.31.1
ubuntu/linux-riscv<7.0.0-31.31.1
7.0.0-31.31.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.6.150.1-1
  2. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 6.8.0-147.147
  3. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 6.8.0-1067.70
  4. Upgrade

    Upgrade ubuntu/linux-aws-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1012.12~24.04.1
  5. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 6.8.0-1071.79
  6. Upgrade

    Upgrade ubuntu/linux-azure-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1014.14~24.04.1
  7. Upgrade

    Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.

    Fixed in 6.8.0-1069.76
  8. Upgrade

    Upgrade ubuntu/linux-azure-fde-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1013.13~24.04.1
  9. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 6.8.0-1071.79
  10. Upgrade

    Upgrade ubuntu/linux-gcp-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1011.11~24.04.1
  11. Upgrade

    Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.

    Fixed in 6.8.0-1066.74
  12. Upgrade

    Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.

    Fixed in 6.8.0-1052.56
  13. Upgrade

    Upgrade ubuntu/linux-hwe-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-31.31~24.04.1
  14. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 6.8.0-1067.68
  15. Upgrade

    Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.

    Fixed in 6.8.0-147.147.1
  16. Upgrade

    Upgrade ubuntu/linux-nvidia-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1018.18~24.04.1
  17. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 6.8.0-1064.67
  18. Upgrade

    Upgrade ubuntu/linux-oracle-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1011.11~24.04.1
  19. Upgrade

    Upgrade ubuntu/linux-riscv-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-31.31.1~24.04.1
  20. Upgrade

    Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.

    Fixed in 6.8.0-1033.38
  21. Upgrade

    Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.

    Fixed in 6.8.1-1062.63
  22. Upgrade

    Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-1067.70+fips1
  23. Upgrade

    Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-1071.79+fips1
  24. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-147.147+fips1
  25. Upgrade

    Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-1071.79+fips1
  26. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 7.0.0-31.31
  27. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 7.0.0-1012.12
  28. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 7.0.0-1014.14
  29. Upgrade

    Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.

    Fixed in 7.0.0-1013.13
  30. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 7.0.0-1011.11
  31. Upgrade

    Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.

    Fixed in 7.0.0-1006.7
  32. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 7.0.0-1013.13
  33. Upgrade

    Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.

    Fixed in 7.0.0-1018.18
  34. Upgrade

    Upgrade ubuntu/linux-nvidia-bos to a version that resolves this vulnerability.

    Fixed in 7.0.0-2018.18
  35. Upgrade

    Upgrade ubuntu/linux-oem-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1013.13
  36. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 7.0.0-1011.11
  37. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 7.0.0-1019.19
  38. Upgrade

    Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.

    Fixed in 7.0.0-31.31.1
  39. Upgrade

    Upgrade ubuntu/linux-riscv to a version that resolves this vulnerability.

    Fixed in 7.0.0-31.31.1
  40. Compensating control

    In rtw_usb_write_data() and rtw_usb_tx_agg_skb(), check the return value of rtw_usb_write_port(); if submission fails, explicitly free the skb in rtw_usb_write_data(), and purge tx_ack_queue and free the txcb in rtw_usb_tx_agg_skb().

Event History

Jul 19, 2026
CVE Published
via MITRE·12:02 PM
Data Sourced
via MITRE·12:02 PM
Description
Data Sourced
via OSV·12:16 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·12:16 PM
Description
Jul 20, 2026
Data Sourced
via Microsoft·08:06 AM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-63821?

CVE-2026-63821 has a risk rating of 17, indicating a moderate-severity vulnerability.

2

How do I fix CVE-2026-63821?

To fix CVE-2026-63821, users should update to the latest version of the Linux kernel where the vulnerability has been patched.

3

What systems are affected by CVE-2026-63821?

CVE-2026-63821 affects the Linux kernel's rtw88 driver related to USB connectivity.

4

What impact does CVE-2026-63821 have?

The impact of CVE-2026-63821 can lead to memory leaks on USB write failures due to incomplete processing.

5

When was CVE-2026-63821 published?

CVE-2026-63821 was published on July 19, 2026.

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