{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "e6e912c4964ce5976e508881207dfa96d5f856d7"
            },
            {
              "fixed": "c321dc5172c8c66e21ffbeeb7a2ebb88ae6fd4c3"
            },
            {
              "fixed": "3ce24bc4d115336218e59b7e286fd3a79f4fc4c6"
            },
            {
              "fixed": "7795e8abedc86438cae0454602cbf9038b94bf38"
            },
            {
              "fixed": "1423415471274abda87024967d7fe2206ceee0ea"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.36"
            },
            {
              "fixed": "6.12.106"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.45"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74653.json"
  },
  "details": "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.",
  "id": "CVE-2026-74653",
  "modified": "2026-08-28T03:30:31.856142506Z",
  "published": "2026-08-22T15:32:28.521Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1423415471274abda87024967d7fe2206ceee0ea"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3ce24bc4d115336218e59b7e286fd3a79f4fc4c6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7795e8abedc86438cae0454602cbf9038b94bf38"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c321dc5172c8c66e21ffbeeb7a2ebb88ae6fd4c3"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74653.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74653"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx"
}