CVE-2026-80622 (GCVE-0-2026-80622)
Vulnerability from cvelistv5
Published
2026-08-28 06:48
Modified
2026-08-29 06:21
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
char: tlclk: fix use-after-free in tlclk_cleanup()
This patch improves the module cleanup process in the tlclk driver to
prevent potential use-after-free and race conditions.
Currently, the file_operations structure does not specify the .owner
field, which could allow the module to be unloaded while user-space
processes are still interacting with the device. Additionally, the
tlclk_cleanup() function frees the alarm_events memory before ensuring
that blocked processes in the waitqueue are fully awakened and that the
switchover_timer has completed.
To address these cases, this patch:
- Sets '.owner = THIS_MODULE' in tlclk_fops to safely defer module
unloading while the device is in use.
- Updates tlclk_cleanup() to explicitly wake up all blocked readers
(wake_up_all), properly release hardware I/O regions, and safely
delete the timer (timer_delete_sync) prior to freeing memory.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 1a80ba88273097933f93b1f40537337416798c70 Version: 1a80ba88273097933f93b1f40537337416798c70 Version: 1a80ba88273097933f93b1f40537337416798c70 Version: 1a80ba88273097933f93b1f40537337416798c70 Version: 1a80ba88273097933f93b1f40537337416798c70 Version: 1a80ba88273097933f93b1f40537337416798c70 Version: 1a80ba88273097933f93b1f40537337416798c70 Version: 1a80ba88273097933f93b1f40537337416798c70 |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/char/tlclk.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "1a80ba88273097933f93b1f40537337416798c70",
"versionType": "git"
},
{
"lessThan": "96902299a22d126ef5eb3f45cd5d8ceea9e6a735",
"status": "affected",
"version": "1a80ba88273097933f93b1f40537337416798c70",
"versionType": "git"
},
{
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"status": "affected",
"version": "1a80ba88273097933f93b1f40537337416798c70",
"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
},
{
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"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/char/tlclk.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.15"
},
{
"lessThan": "2.6.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"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": "5.10.261",
"versionStartIncluding": "2.6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.212",
"versionStartIncluding": "2.6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.178",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.97",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.40",
"versionStartIncluding": "2.6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.5",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "2.6.15",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nchar: tlclk: fix use-after-free in tlclk_cleanup()\n\nThis patch improves the module cleanup process in the tlclk driver to\nprevent potential use-after-free and race conditions.\n\nCurrently, the file_operations structure does not specify the .owner\nfield, which could allow the module to be unloaded while user-space\nprocesses are still interacting with the device. Additionally, the\ntlclk_cleanup() function frees the alarm_events memory before ensuring\nthat blocked processes in the waitqueue are fully awakened and that the\nswitchover_timer has completed.\n\nTo address these cases, this patch:\n- Sets \u0027.owner = THIS_MODULE\u0027 in tlclk_fops to safely defer module\n unloading while the device is in use.\n- Updates tlclk_cleanup() to explicitly wake up all blocked readers\n (wake_up_all), properly release hardware I/O regions, and safely\n delete the timer (timer_delete_sync) prior to freeing memory."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The UAF is reached only via local open/read syscalls on /dev/telco_clock and tlclk_cleanup() during delete_module/rmmod; this x86 ATCA telecom-clock char driver has no network, Bluetooth, or physical-bus attack surface.\nAC:L - Without .owner the attacker controls both sides of the race by keeping /dev/telco_clock open with read() blocked on wq while IRQs remain active, then timing or piggybacking on module unload to hit kfree(alarm_events) against tlclk_read, tlclk_interrupt, or switchover_timeout.\nPR:L - An unprivileged local user with /dev/telco_clock access can open the device and block in read() while IRQs stay registered; per CNA driver-removal UAF precedent, concurrent admin rmmod triggering tlclk_cleanup() does not require the attacker to hold CAP_SYS_MODULE.\nUI:N - No victim interaction is required; the attacker opens /dev/telco_clock and blocks on read() or sustains IRQ/timer activity themselves while module unload occurs during maintenance or coordinated rmmod, without needing another user to act.\nS:U - Kernel heap UAF during tlclk module cleanup affects only the host kernel on the ATCA blade; this is standard in-kernel memory corruption, not a VM escape, IOMMU bypass, or cross-authority sandbox breakout.\nC:H - tlclk_read() performs copy_to_user from freed alarm_events, and tlclk_interrupt/switchover_timeout dereference the freed buffer; this kernel heap UAF enables arbitrary read primitives via controlled slab reuse and information disclosure.\nI:H - tlclk_read() memset() on freed alarm_events and IRQ/timer handlers increment fields in the freed structure, providing kernel heap write primitives exploitable for control-flow hijack via slab spraying and UAF exploitation.\nA:H - Concurrent access to freed alarm_events from read(), switchover_timeout, or tlclk_interrupt during module unload can cause kernel oops/panic; UAF during driver teardown reliably threatens system availability even when not fully weaponized."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-29T06:21:27.766Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/09d8d2a46a9ec9ff728f3159a174a2ab25dd0f0a"
},
{
"url": "https://git.kernel.org/stable/c/96902299a22d126ef5eb3f45cd5d8ceea9e6a735"
},
{
"url": "https://git.kernel.org/stable/c/166dd1d5265e067459e674c11688919901813ec2"
},
{
"url": "https://git.kernel.org/stable/c/764723bd67a6c8f53a8d8309211fb039e2ebcf49"
},
{
"url": "https://git.kernel.org/stable/c/c3f0cd76561ae611c2d247ee96dfd559e4197cb7"
},
{
"url": "https://git.kernel.org/stable/c/3d5e4cc0d9dce79b0429da3134ac7b072ab9009f"
},
{
"url": "https://git.kernel.org/stable/c/42223445607a9a5df3cb1c4729abfe3a5085e7ce"
},
{
"url": "https://git.kernel.org/stable/c/bbf003b7794d6ad6f939fdd29f1f1bde8ac554c1"
}
],
"title": "char: tlclk: fix use-after-free in tlclk_cleanup()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-80622",
"datePublished": "2026-08-28T06:48:41.744Z",
"dateReserved": "2026-08-26T14:34:25.775Z",
"dateUpdated": "2026-08-29T06:21:27.766Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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