CVE-2026-63821
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:
- A memory leak of the allocated skb in rtw_usb_write_data().
- 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.
No affected software listed.
- https://git.kernel.org/stable/c/200d58c851b8f63f77a05570072dd20f79bc3681
- https://git.kernel.org/stable/c/2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb
- https://git.kernel.org/stable/c/53fed4061a09755de99c89fdc7fae5b794da455f
- https://git.kernel.org/stable/c/6b964941bbfe6e0f18b1a5e008486dbb62df440a
- https://git.kernel.org/stable/c/8206d173d18ef5a077423119f4e9a93cb3a6f4eb
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A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
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