--- cve: "CVE-2026-63821" severity: "LOW" cvss: 3.1 epss: "0.2%" vendor: "Linux" kev: false exploited: false published: "2026-07-19 12:16:55" tags: [cve, security, low] source: tsecurity.de CVE-Dossier exported: "2026-09-21T22:27:52+02:00" --- # CVE-2026-63821 > 3.1 LOW ## Beschreibung In the Linux kernel, the following vulnerability has been resolved: wifi: rtw88: usb: fix memory leaks on USB write failures When rtw_usb_write_port() 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 rtw_usb_write_port() in rtw_usb_write_data() and rtw_usb_tx_agg_skb(). 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 rtw_usb_write_data(). 2. A memory leak of the txcb structure and all aggregated skbs in rtw_usb_tx_agg_skb(). Fix this by checking the return value of rtw_usb_write_port(). If it fails, explicitly free the skb in rtw_usb_write_data(), and properly purge the tx_ack_queue and free the txcb in rtw_usb_tx_agg_skb(). 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. ## Patch verfügbar (OSV) - Kernel ≥ 6.6.144 - Kernel ≥ 6.12.95 - Kernel ≥ 6.18.38 - Kernel ≥ 7.1.3 ## Referenzen - - - - - --- _Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-63821) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_