CVE-2026-63821 (GCVE-0-2026-63821)
Vulnerability from cvelistv5 – Published: 2026-07-19 12:02 – Updated: 2026-08-17 04:51
VLAI
EPSS
VEX
Title
wifi: rtw88: usb: fix memory leaks on USB write failures
Summary
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
a82dfd33d1237f6c0fb8a7077022189d1fc7ec98 , < 2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb
(git)
Affected: a82dfd33d1237f6c0fb8a7077022189d1fc7ec98 , < 53fed4061a09755de99c89fdc7fae5b794da455f (git) Affected: a82dfd33d1237f6c0fb8a7077022189d1fc7ec98 , < 200d58c851b8f63f77a05570072dd20f79bc3681 (git) Affected: a82dfd33d1237f6c0fb8a7077022189d1fc7ec98 , < 8206d173d18ef5a077423119f4e9a93cb3a6f4eb (git) Affected: a82dfd33d1237f6c0fb8a7077022189d1fc7ec98 , < 6b964941bbfe6e0f18b1a5e008486dbb62df440a (git) |
guessed | |
| Linux | Linux |
Affected:
6.2
Unaffected: 0 , < 6.2 (semver) Unaffected: 6.6.144 , ≤ 6.6.* (semver) Unaffected: 6.12.95 , ≤ 6.12.* (semver) Unaffected: 6.18.38 , ≤ 6.18.* (semver) Unaffected: 7.1.3 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/wireless/realtek/rtw88/usb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb",
"status": "affected",
"version": "a82dfd33d1237f6c0fb8a7077022189d1fc7ec98",
"versionType": "git"
},
{
"lessThan": "53fed4061a09755de99c89fdc7fae5b794da455f",
"status": "affected",
"version": "a82dfd33d1237f6c0fb8a7077022189d1fc7ec98",
"versionType": "git"
},
{
"lessThan": "200d58c851b8f63f77a05570072dd20f79bc3681",
"status": "affected",
"version": "a82dfd33d1237f6c0fb8a7077022189d1fc7ec98",
"versionType": "git"
},
{
"lessThan": "8206d173d18ef5a077423119f4e9a93cb3a6f4eb",
"status": "affected",
"version": "a82dfd33d1237f6c0fb8a7077022189d1fc7ec98",
"versionType": "git"
},
{
"lessThan": "6b964941bbfe6e0f18b1a5e008486dbb62df440a",
"status": "affected",
"version": "a82dfd33d1237f6c0fb8a7077022189d1fc7ec98",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/wireless/realtek/rtw88/usb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.2"
},
{
"lessThan": "6.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.144",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.95",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.38",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.144",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.95",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.38",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.3",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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), 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."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:51:28.975Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb"
},
{
"url": "https://git.kernel.org/stable/c/53fed4061a09755de99c89fdc7fae5b794da455f"
},
{
"url": "https://git.kernel.org/stable/c/200d58c851b8f63f77a05570072dd20f79bc3681"
},
{
"url": "https://git.kernel.org/stable/c/8206d173d18ef5a077423119f4e9a93cb3a6f4eb"
},
{
"url": "https://git.kernel.org/stable/c/6b964941bbfe6e0f18b1a5e008486dbb62df440a"
}
],
"title": "wifi: rtw88: usb: fix memory leaks on USB write failures",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-63821",
"datePublished": "2026-07-19T12:02:18.751Z",
"dateReserved": "2026-07-19T07:54:57.014Z",
"dateUpdated": "2026-08-17T04:51:28.975Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-63821",
"date": "2026-10-20",
"epss": "0.00166",
"percentile": "0.05446"
},
"microsoft_vex": {
"current_release_date": "2026-08-14T18:33:23.000Z",
"cve": "CVE-2026-63821",
"id": "msrc_CVE-2026-63821",
"initial_release_date": "2026-07-20T01:06:05.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "wifi: rtw88: usb: fix memory leaks on USB write failures",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-63821.json",
"version": "7"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/wireless/realtek/rtw88/usb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "a82dfd33d1237f6c0fb8a7077022189d1fc7ec98",
"versionType": "git"
},
{
"lessThan": "53fed4061a09755de99c89fdc7fae5b794da455f",
"status": "affected",
"version": "a82dfd33d1237f6c0fb8a7077022189d1fc7ec98",
"versionType": "git"
},
{
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"versionType": "git"
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"versionType": "git"
},
{
"lessThan": "6b964941bbfe6e0f18b1a5e008486dbb62df440a",
"status": "affected",
"version": "a82dfd33d1237f6c0fb8a7077022189d1fc7ec98",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/wireless/realtek/rtw88/usb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.2"
},
{
"lessThan": "6.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.144",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.95",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.38",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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), 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."
}
],
"id": "CVE-2026-63821",
"lastModified": "2026-08-17T05:17:19.573",
"metrics": {},
"published": "2026-07-19T12:16:55.203",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/200d58c851b8f63f77a05570072dd20f79bc3681"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/53fed4061a09755de99c89fdc7fae5b794da455f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6b964941bbfe6e0f18b1a5e008486dbb62df440a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8206d173d18ef5a077423119f4e9a93cb3a6f4eb"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
}
},
"redhat_vex": {
"aggregate_severity": "Low",
"current_release_date": "2026-08-07T11:20:50+00:00",
"cve": "CVE-2026-63821",
"id": "CVE-2026-63821",
"initial_release_date": "2026-07-19T00:00:00+00:00",
"product_status:known_affected": "184",
"product_status:known_not_affected": "90",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: wifi: rtw88: usb: fix memory leaks on USB write failures",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63821.json",
"version": "3"
}
}
}
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