{"id":"CVE-2023-53094","state":"PUBLISHED","title":"tty: serial: fsl_lpuart: fix race on RX DMA shutdown","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntty: serial: fsl_lpuart: fix race on RX DMA shutdown\n\nFrom time to time DMA completion can come in the middle of DMA shutdown:\n\n<process ctx>:\t\t\t\t<IRQ>:\nlpuart32_shutdown()\n  lpuart_dma_shutdown()\n    del_timer_sync()\n\t\t\t\t\tlpuart_dma_rx_complete()\n\t\t\t\t\t  lpuart_copy_rx_to_tty()\n\t\t\t\t\t    mod_timer()\n    lpuart_dma_rx_free()\n\nWhen the timer fires a bit later, sport->dma_rx_desc is NULL:\n\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000004\npc : lpuart_copy_rx_to_tty+0xcc/0x5bc\nlr : lpuart_timer_func+0x1c/0x2c\nCall trace:\n lpuart_copy_rx_to_tty\n lpuart_timer_func\n call_timer_fn\n __run_timers.part.0\n run_timer_softirq\n __do_softirq\n __irq_exit_rcu\n irq_exit\n handle_domain_irq\n gic_handle_irq\n call_on_irq_stack\n do_interrupt_handler\n ...\n\nTo fix this fold del_timer_sync() into lpuart_dma_rx_free() after\ndmaengine_terminate_sync() to make sure timer will not be re-started in\nlpuart_copy_rx_to_tty() <= lpuart_dma_rx_complete().","publishedAt":"2025-05-02T15:55:39.045Z","updatedAt":"2026-08-05T09:12:45.604Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"19a98d56dfedafb25652bdb9cd48a4e73ceba702","versionType":"git"},{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"90530e7214c8a04dcdde57502d93fa96af288c38","versionType":"git"},{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"954fc9931f0aabf272b5674cf468affdd88d3a36","versionType":"git"},{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"2a36b444cace9580380467fd1183bb5e85bcc80a","versionType":"git"},{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"1be6f2b15f902c02e055ae0b419ca789200473c9","versionType":"git"},{"version":"5716a781032693d0f812ed06528d98195e9df028","status":"affected","versionType":"git"},{"version":"0d5cb6e8b4b62d8efd1a470615894276341d6db9","status":"affected","versionType":"git"},{"version":"3.18.9","status":"affected","lessThan":"3.19","versionType":"semver"},{"version":"3.19.1","status":"affected","lessThan":"3.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/tty/serial/fsl_lpuart.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.0","versionType":"semver"},{"version":"5.10.177","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.105","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.23","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.8","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/tty/serial/fsl_lpuart.c"]}],"references":["https://git.kernel.org/stable/c/19a98d56dfedafb25652bdb9cd48a4e73ceba702","https://git.kernel.org/stable/c/90530e7214c8a04dcdde57502d93fa96af288c38","https://git.kernel.org/stable/c/954fc9931f0aabf272b5674cf468affdd88d3a36","https://git.kernel.org/stable/c/2a36b444cace9580380467fd1183bb5e85bcc80a","https://git.kernel.org/stable/c/1be6f2b15f902c02e055ae0b419ca789200473c9"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53094.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53094","state":"PUBLISHED","datePublished":"2025-05-02T15:55:39.045Z","dateUpdated":"2026-08-05T09:12:45.604Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-05-02T15:51:43.552Z"},"containers":{"cna":{"title":"tty: serial: fsl_lpuart: fix race on RX DMA shutdown","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntty: serial: fsl_lpuart: fix race on RX DMA shutdown\n\nFrom time to time DMA completion can come in the middle of DMA shutdown:\n\n<process ctx>:\t\t\t\t<IRQ>:\nlpuart32_shutdown()\n  lpuart_dma_shutdown()\n    del_timer_sync()\n\t\t\t\t\tlpuart_dma_rx_complete()\n\t\t\t\t\t  lpuart_copy_rx_to_tty()\n\t\t\t\t\t    mod_timer()\n    lpuart_dma_rx_free()\n\nWhen the timer fires a bit later, sport->dma_rx_desc is NULL:\n\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000004\npc : lpuart_copy_rx_to_tty+0xcc/0x5bc\nlr : lpuart_timer_func+0x1c/0x2c\nCall trace:\n lpuart_copy_rx_to_tty\n lpuart_timer_func\n call_timer_fn\n __run_timers.part.0\n run_timer_softirq\n __do_softirq\n __irq_exit_rcu\n irq_exit\n handle_domain_irq\n gic_handle_irq\n call_on_irq_stack\n do_interrupt_handler\n ...\n\nTo fix this fold del_timer_sync() into lpuart_dma_rx_free() after\ndmaengine_terminate_sync() to make sure timer will not be re-started in\nlpuart_copy_rx_to_tty() <= lpuart_dma_rx_complete()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"19a98d56dfedafb25652bdb9cd48a4e73ceba702","versionType":"git"},{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"90530e7214c8a04dcdde57502d93fa96af288c38","versionType":"git"},{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"954fc9931f0aabf272b5674cf468affdd88d3a36","versionType":"git"},{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"2a36b444cace9580380467fd1183bb5e85bcc80a","versionType":"git"},{"version":"4a8588a1cf867333187d9ff071e6fbdab587d194","status":"affected","lessThan":"1be6f2b15f902c02e055ae0b419ca789200473c9","versionType":"git"},{"version":"5716a781032693d0f812ed06528d98195e9df028","status":"affected","versionType":"git"},{"version":"0d5cb6e8b4b62d8efd1a470615894276341d6db9","status":"affected","versionType":"git"},{"version":"3.18.9","status":"affected","lessThan":"3.19","versionType":"semver"},{"version":"3.19.1","status":"affected","lessThan":"3.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/tty/serial/fsl_lpuart.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.0","versionType":"semver"},{"version":"5.10.177","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.105","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.23","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.8","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/tty/serial/fsl_lpuart.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/19a98d56dfedafb25652bdb9cd48a4e73ceba702"},{"url":"https://git.kernel.org/stable/c/90530e7214c8a04dcdde57502d93fa96af288c38"},{"url":"https://git.kernel.org/stable/c/954fc9931f0aabf272b5674cf468affdd88d3a36"},{"url":"https://git.kernel.org/stable/c/2a36b444cace9580380467fd1183bb5e85bcc80a"},{"url":"https://git.kernel.org/stable/c/1be6f2b15f902c02e055ae0b419ca789200473c9"}],"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 vulnerable RX DMA shutdown path is reached via local tty operations (close → uart_shutdown, or tcsetattr → set_termios) on the fsl_lpuart device node (/dev/ttyLP*), not via network packets or a required physical plug-in attack.\nAC:L - An attacker who can open the LPUART tty controls the shutdown/set_termios side and can generate continuous UART RX (serial peer, Bluetooth HCI-over-UART traffic, or similar) to drive DMA completion IRQs, so both sides of the race are attacker-influenced and retryable.\nPR:L - Exploitation requires opening the serial tty device as an unprivileged local user with ordinary device permissions (e.g. dialout/tty group), not real root or init-namespace admin capabilities.\nUI:N - The attacker triggers the race themselves by opening the port and closing it or changing termios while RX DMA is active; no separate victim action is required.\nS:U - Impact stays within the kernel/host security authority (crash or memory corruption in the serial driver); this is not a VM escape, IOMMU bypass, or other cross-boundary breakout.\nC:H - After del_timer_sync, a DMA completion can re-arm the timer before lpuart_dma_rx_free finishes; the timer may run after kfree(rx_ring.buf) while dma_rx_desc is still non-NULL, so lpuart_copy_rx_to_tty can read freed DMA buffer contents into the tty flip buffer (UAF disclosure), especially on the set_termios path where the fd stays open.\nI:H - The same race yields use-after-free / dangling use of the DMA descriptor and RX ring (async_tx_ack writes through dma_rx_desc after terminate_sync may have recycled it, plus use of freed buffer state), which is memory corruption exploitable beyond a clean crash.\nA:H - The commonly observed outcome is a kernel NULL pointer dereference in lpuart_copy_rx_to_tty from lpuart_timer_func (oops/panic), and the UAF paths similarly cause reliable kernel crashes."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T09:12:45.604Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.10.177"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.15.105"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.1.23"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.2.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}