{"api_version":"1","generated_at":"2026-08-22T18:40:14+00:00","cve":"CVE-2026-74653","urls":{"html":"https://cve.report/CVE-2026-74653","api":"https://cve.report/api/cve/CVE-2026-74653.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74653","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74653"},"summary":{"title":"serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nserial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx\n\nThe NXP LPC32xx UART (PORT_LPC3220) can latch an RX character-timeout\ninterrupt while the RX FIFO is empty: IIR reports UART_IIR_RX_TIMEOUT\n(0x0c) but LSR.DR is clear. A character timeout is only cleared by\nreading RHR, but serial8250_rx_chars() reads RHR only when LSR.DR is\nset, so nothing ever clears the condition. The interrupt is\nlevel-triggered and re-fires immediately, so on a single-core ARM926\nthe resulting interrupt storm livelocks the CPU.\n\nIt is reproducible when userspace repeatedly opens the front-panel port\n(ttyS1): serial8250_do_set_termios() re-enables interrupts on unlock and\nthe handler then spins forever with iir=0xcc lsr=0x60 ier=0x05, tripping\nthe soft-lockup detector in serial8250_handle_irq_locked().\n\nLPC32xx has no dedicated 8250 glue driver, it's driven by the generic\n8250_of. Add a hardware specific handle_irq for PORT_LPC3220, wired up\nin of_platform_serial_setup() the same way fsl8250_handle_irq is\ninstalled. The handler follows dw8250_handle_irq(): on an RX timeout\nwith an empty FIFO (LSR.DR and LSR.BI clear) it does one throwaway RHR\nread to clear the condition, then calls serial8250_handle_irq_locked().\nNo real received data is ever discarded, and it is a no-op on healthy\nUARTs which never report a timeout with DR clear.\n\nThis is the same class of bug already worked around in other 8250 drivers;\nsee commit 424d79183af0 (\"serial: 8250_dw: Avoid \"too much work\" from bogus rx timeout interrupt\")\nwhich reports the identical iir=0xcc/lsr=0x60. See also\nUART_RX_TIMEOUT_QUIRK in 8250_omap, and the note in 8250_bcm7271.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-22 16:16:38","updated_at":"2026-08-22 16:16:38"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/7795e8abedc86438cae0454602cbf9038b94bf38","name":"https://git.kernel.org/stable/c/7795e8abedc86438cae0454602cbf9038b94bf38","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1423415471274abda87024967d7fe2206ceee0ea","name":"https://git.kernel.org/stable/c/1423415471274abda87024967d7fe2206ceee0ea","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3ce24bc4d115336218e59b7e286fd3a79f4fc4c6","name":"https://git.kernel.org/stable/c/3ce24bc4d115336218e59b7e286fd3a79f4fc4c6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74653","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74653","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 3ce24bc4d115336218e59b7e286fd3a79f4fc4c6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 7795e8abedc86438cae0454602cbf9038b94bf38 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 1423415471274abda87024967d7fe2206ceee0ea git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18.45 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.1.9 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.45 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.9 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/tty/serial/8250/8250_of.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"3ce24bc4d115336218e59b7e286fd3a79f4fc4c6","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"7795e8abedc86438cae0454602cbf9038b94bf38","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"1423415471274abda87024967d7fe2206ceee0ea","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"6.18.45","status":"affected","version":"0","versionType":"semver"},{"lessThan":"7.1.9","status":"affected","version":"0","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/tty/serial/8250/8250_of.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.45","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.9","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":"6.18.45","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nserial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx\n\nThe NXP LPC32xx UART (PORT_LPC3220) can latch an RX character-timeout\ninterrupt while the RX FIFO is empty: IIR reports UART_IIR_RX_TIMEOUT\n(0x0c) but LSR.DR is clear. A character timeout is only cleared by\nreading RHR, but serial8250_rx_chars() reads RHR only when LSR.DR is\nset, so nothing ever clears the condition. The interrupt is\nlevel-triggered and re-fires immediately, so on a single-core ARM926\nthe resulting interrupt storm livelocks the CPU.\n\nIt is reproducible when userspace repeatedly opens the front-panel port\n(ttyS1): serial8250_do_set_termios() re-enables interrupts on unlock and\nthe handler then spins forever with iir=0xcc lsr=0x60 ier=0x05, tripping\nthe soft-lockup detector in serial8250_handle_irq_locked().\n\nLPC32xx has no dedicated 8250 glue driver, it's driven by the generic\n8250_of. Add a hardware specific handle_irq for PORT_LPC3220, wired up\nin of_platform_serial_setup() the same way fsl8250_handle_irq is\ninstalled. The handler follows dw8250_handle_irq(): on an RX timeout\nwith an empty FIFO (LSR.DR and LSR.BI clear) it does one throwaway RHR\nread to clear the condition, then calls serial8250_handle_irq_locked().\nNo real received data is ever discarded, and it is a no-op on healthy\nUARTs which never report a timeout with DR clear.\n\nThis is the same class of bug already worked around in other 8250 drivers;\nsee commit 424d79183af0 (\"serial: 8250_dw: Avoid \"too much work\" from bogus rx timeout interrupt\")\nwhich reports the identical iir=0xcc/lsr=0x60. See also\nUART_RX_TIMEOUT_QUIRK in 8250_omap, and the note in 8250_bcm7271."}],"providerMetadata":{"dateUpdated":"2026-08-22T15:32:28.521Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/3ce24bc4d115336218e59b7e286fd3a79f4fc4c6"},{"url":"https://git.kernel.org/stable/c/7795e8abedc86438cae0454602cbf9038b94bf38"},{"url":"https://git.kernel.org/stable/c/1423415471274abda87024967d7fe2206ceee0ea"}],"title":"serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74653","datePublished":"2026-08-22T15:32:28.521Z","dateReserved":"2026-08-15T05:44:03.923Z","dateUpdated":"2026-08-22T15:32:28.521Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-22 16:16:38","lastModifiedDate":"2026-08-22 16:16:38","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74653","Ordinal":"1","Title":"serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx","CVE":"CVE-2026-74653","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74653","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nserial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx\n\nThe NXP LPC32xx UART (PORT_LPC3220) can latch an RX character-timeout\ninterrupt while the RX FIFO is empty: IIR reports UART_IIR_RX_TIMEOUT\n(0x0c) but LSR.DR is clear. A character timeout is only cleared by\nreading RHR, but serial8250_rx_chars() reads RHR only when LSR.DR is\nset, so nothing ever clears the condition. The interrupt is\nlevel-triggered and re-fires immediately, so on a single-core ARM926\nthe resulting interrupt storm livelocks the CPU.\n\nIt is reproducible when userspace repeatedly opens the front-panel port\n(ttyS1): serial8250_do_set_termios() re-enables interrupts on unlock and\nthe handler then spins forever with iir=0xcc lsr=0x60 ier=0x05, tripping\nthe soft-lockup detector in serial8250_handle_irq_locked().\n\nLPC32xx has no dedicated 8250 glue driver, it's driven by the generic\n8250_of. Add a hardware specific handle_irq for PORT_LPC3220, wired up\nin of_platform_serial_setup() the same way fsl8250_handle_irq is\ninstalled. The handler follows dw8250_handle_irq(): on an RX timeout\nwith an empty FIFO (LSR.DR and LSR.BI clear) it does one throwaway RHR\nread to clear the condition, then calls serial8250_handle_irq_locked().\nNo real received data is ever discarded, and it is a no-op on healthy\nUARTs which never report a timeout with DR clear.\n\nThis is the same class of bug already worked around in other 8250 drivers;\nsee commit 424d79183af0 (\"serial: 8250_dw: Avoid \"too much work\" from bogus rx timeout interrupt\")\nwhich reports the identical iir=0xcc/lsr=0x60. See also\nUART_RX_TIMEOUT_QUIRK in 8250_omap, and the note in 8250_bcm7271.","Type":"Description","Title":"serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx"}]}}}