{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80622","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.775Z","datePublished":"2026-08-28T06:48:41.744Z","dateUpdated":"2026-08-29T06:21:27.766Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-29T06:21:27.766Z"},"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 '.owner = THIS_MODULE' 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":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/char/tlclk.c"],"versions":[{"version":"1a80ba88273097933f93b1f40537337416798c70","lessThan":"09d8d2a46a9ec9ff728f3159a174a2ab25dd0f0a","status":"affected","versionType":"git"},{"version":"1a80ba88273097933f93b1f40537337416798c70","lessThan":"96902299a22d126ef5eb3f45cd5d8ceea9e6a735","status":"affected","versionType":"git"},{"version":"1a80ba88273097933f93b1f40537337416798c70","lessThan":"166dd1d5265e067459e674c11688919901813ec2","status":"affected","versionType":"git"},{"version":"1a80ba88273097933f93b1f40537337416798c70","lessThan":"764723bd67a6c8f53a8d8309211fb039e2ebcf49","status":"affected","versionType":"git"},{"version":"1a80ba88273097933f93b1f40537337416798c70","lessThan":"c3f0cd76561ae611c2d247ee96dfd559e4197cb7","status":"affected","versionType":"git"},{"version":"1a80ba88273097933f93b1f40537337416798c70","lessThan":"3d5e4cc0d9dce79b0429da3134ac7b072ab9009f","status":"affected","versionType":"git"},{"version":"1a80ba88273097933f93b1f40537337416798c70","lessThan":"42223445607a9a5df3cb1c4729abfe3a5085e7ce","status":"affected","versionType":"git"},{"version":"1a80ba88273097933f93b1f40537337416798c70","lessThan":"bbf003b7794d6ad6f939fdd29f1f1bde8ac554c1","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/char/tlclk.c"],"versions":[{"version":"2.6.15","status":"affected"},{"version":"0","lessThan":"2.6.15","status":"unaffected","versionType":"semver"},{"version":"5.10.261","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.212","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.178","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.145","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.97","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.40","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.5","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"5.10.261"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"7.2"}]}]}],"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"}}}}