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

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 6.2版本存在安全漏洞，该漏洞源于rtw88 USB驱动程序中的rtw_usb_write_port()函数在提交USB请求块失败时未释放套接字缓冲区和事务控制块，可能导致内存泄漏。

AI Predicted 5.5 Difficulty: Easy EPSS 0.17% · P7

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux a82dfd33d1237f6c0fb8a7077022189d1fc7ec98< 2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb affected
a82dfd33d1237f6c0fb8a7077022189d1fc7ec98< 53fed4061a09755de99c89fdc7fae5b794da455f affected
a82dfd33d1237f6c0fb8a7077022189d1fc7ec98< 200d58c851b8f63f77a05570072dd20f79bc3681 affected
a82dfd33d1237f6c0fb8a7077022189d1fc7ec98< 8206d173d18ef5a077423119f4e9a93cb3a6f4eb affected
a82dfd33d1237f6c0fb8a7077022189d1fc7ec98< 6b964941bbfe6e0f18b1a5e008486dbb62df440a affected
6.2 affected
< 6.2 unaffected
6.6.144≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-63821

Vulnerability Information
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Vulnerability Title
wifi: rtw88: usb: fix memory leaks on USB write failures
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 6.2版本存在安全漏洞，该漏洞源于rtw88 USB驱动程序中的rtw_usb_write_port()函数在提交USB请求块失败时未释放套接字缓冲区和事务控制块，可能导致内存泄漏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux a82dfd33d1237f6c0fb8a7077022189d1fc7ec98 ~ 2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb -
Linux Linux 6.2 -

II. Public POCs for CVE-2026-63821

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III. Intelligence Information for CVE-2026-63821

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Patches & Fixes for CVE-2026-63821 (5)

Same Patch Batch · Linux · 2026-07-19 · 429 CVEs total

CVE-2026-63795 10.0 CRITICAL 9p: avoid putting oldfid in p9_client_walk() error path
CVE-2026-64046 9.8 CRITICAL net: tls: prevent chain-after-chain in plain text SG
CVE-2026-63984 9.8 CRITICAL ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress()
CVE-2026-63979 9.8 CRITICAL net/handshake: hand off the pinned file reference to accept_doit
CVE-2026-63800 9.8 CRITICAL pNFS: Fix use-after-free in pnfs_update_layout()
CVE-2026-64142 9.8 CRITICAL ksmbd: close durable scavenger races against m_fp_list lookups
CVE-2026-63978 9.8 CRITICAL net/handshake: Drain pending requests at net namespace exit
CVE-2026-64056 9.8 CRITICAL net: ethernet: cortina: Make RX SKB per-port
CVE-2026-63808 9.8 CRITICAL exfat: fix potential use-after-free in exfat_find_dir_entry()
CVE-2026-64055 9.8 CRITICAL net: ethernet: cortina: Carry over frag counter
CVE-2026-63922 9.8 CRITICAL ipv6: exthdrs: refresh nh after handling HAO option
CVE-2026-64033 9.8 CRITICAL RDMA/rtrs: Fix use-after-free in path file creation cleanup
CVE-2026-64113 9.8 CRITICAL ixgbevf: fix use-after-free in VEPA multicast source pruning
CVE-2026-63825 9.8 CRITICAL gcov: use atomic counter updates to fix concurrent access crashes
CVE-2026-64016 9.8 CRITICAL ksmbd: fix durable reconnect error path file lifetime
CVE-2026-64122 9.8 CRITICAL net/mlx5e: Fix use-after-free in mlx5e_tx_reporter_timeout_recover
CVE-2026-64047 9.8 CRITICAL net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring
CVE-2026-64035 9.8 CRITICAL igc: set tx buffer type for SMD frames
CVE-2026-64025 9.8 CRITICAL bpf, skmsg: fix verdict sk_data_ready racing with ktls rx
CVE-2026-64150 9.8 CRITICAL netfilter: nft_inner: release local_lock before re-enabling softirqs

Showing top 20 of 429 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-63821

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