{"cve":"CVE-2025-39724","nvd":{"published":"2025-09-05T18:15:50.177","modified":"2026-10-19T21:10:00.160","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nserial: 8250: fix panic due to PSLVERR\n\nWhen the PSLVERR_RESP_EN parameter is set to 1, the device generates\nan error response if an attempt is made to read an empty RBR (Receive\nBuffer Register) while the FIFO is enabled.\n\nIn serial8250_do_startup(), calling serial_port_out(port, UART_LCR,\nUART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes\ndw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter\nfunction enables the FIFO via serial_out(p, UART_FCR, p->fcr).\nExecution proceeds to the serial_port_in(port, UART_RX).\nThis satisfies the PSLVERR trigger condition.\n\nWhen another CPU (e.g., using printk()) is accessing the UART (UART\nis busy), the current CPU fails the check (value & ~UART_LCR_SPAR) ==\n(lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter\ndw8250_force_idle().\n\nPut serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock\nto fix this issue.\n\nPanic backtrace:\n[    0.442336] Oops - unknown exception [#1]\n[    0.442343] epc : dw8250_serial_in32+0x1e/0x4a\n[    0.442351]  ra : serial8250_do_startup+0x2c8/0x88e\n...\n[    0.442416] console_on_rootfs+0x26/0x70","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/0b882f00655afefbc7729c6b5aec86f7a5473a3d","https://git.kernel.org/stable/c/38c0ea484dedb58cb3a4391229933e16be0d1031","https://git.kernel.org/stable/c/68c4613e89f000e8198f9ace643082c697921c9f","https://git.kernel.org/stable/c/7f8fdd4dbffc05982b96caf586f77a014b2a9353","https://git.kernel.org/stable/c/8e2739478c164147d0774802008528d9e03fb802"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39724","score":0.00174,"percentile":0.06809,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}