{"id":"CVE-2026-63821","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: rtw88: usb: fix memory leaks on USB write failures\n\nWhen rtw_usb_write_port() fails to submit a USB Request Block (URB)\n(e.g., due to device disconnect or ENOMEM)…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: rtw88: usb: fix memory leaks on USB write failures\n\nWhen rtw_usb_write_port() fails to submit a USB Request Block (URB)\n(e.g., due to device disconnect or ENOMEM)…","severity":"none","published":"2026-07-19","updated":"2026-08-17","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-63821","references":[{"url":"https://git.kernel.org/stable/c/200d58c851b8f63f77a05570072dd20f79bc3681","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/53fed4061a09755de99c89fdc7fae5b794da455f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6b964941bbfe6e0f18b1a5e008486dbb62df440a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8206d173d18ef5a077423119f4e9a93cb3a6f4eb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00166,"epssPercentile":0.05138,"ingestedAt":"2026-08-17T05:47:49.772Z","slug":"CVE-2026-63821","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nwifi: rtw88: usb: fix memory leaks on USB write failures\n\nWhen rtw_usb_write_port() fails to submit a USB Request Block (URB)\n(e.g., due to device disconnect or ENOMEM), the completion callback is\nnever executed.\n\nCurrently, the driver ignores the return value of rtw_usb_write_port()\nin rtw_usb_write_data() and rtw_usb_tx_agg_skb(). Because these\nfunctions rely on the completion callback to free the socket buffers\n(skbs) and the transaction control block (txcb), a submission failure\nresults in:\n1. A memory leak of the allocated skb in rtw_usb_write_data().\n2. A memory leak of the txcb structure and all aggregated skbs in\n   rtw_usb_tx_agg_skb().\n\nFix this by checking the return value of rtw_usb_write_port(). If it\nfails, explicitly free the skb in rtw_usb_write_data(), and properly\npurge the tx_ack_queue and free the txcb in rtw_usb_tx_agg_skb().\n\nThe issue was discovered in practice during device disconnect/reconnect\nscenarios and memory pressure conditions. Tested by verifying normal TX\noperation continues after the fix without regressions.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}