{"cve":"CVE-2025-39784","nvd":{"published":"2025-09-11T17:15:44.493","modified":"2026-10-19T21:10:00.160","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nPCI: Fix link speed calculation on retrain failure\n\nWhen pcie_failed_link_retrain() fails to retrain, it tries to revert to the\nprevious link speed.  However it calculates that speed from the Link\nControl 2 register without masking out non-speed bits first.\n\nPCIE_LNKCTL2_TLS2SPEED() converts such incorrect values to\nPCI_SPEED_UNKNOWN (0xff), which in turn causes a WARN splat in\npcie_set_target_speed():\n\n  pci 0000:00:01.1: [1022:14ed] type 01 class 0x060400 PCIe Root Port\n  pci 0000:00:01.1: broken device, retraining non-functional downstream link at 2.5GT/s\n  pci 0000:00:01.1: retraining failed\n  WARNING: CPU: 1 PID: 1 at drivers/pci/pcie/bwctrl.c:168 pcie_set_target_speed\n  RDX: 0000000000000001 RSI: 00000000000000ff RDI: ffff9acd82efa000\n  pcie_failed_link_retrain\n  pci_device_add\n  pci_scan_single_device\n\nMask out the non-speed bits in PCIE_LNKCTL2_TLS2SPEED() and\nPCIE_LNKCAP_SLS2SPEED() so they don't incorrectly return PCI_SPEED_UNKNOWN.\n\n[bhelgaas: commit log, add details from https://lore.kernel.org/r/1c92ef6bcb314ee6977839b46b393282e4f52e74.1750684771.git.lukas@wunner.de]","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/16557320f378262b5c605b15edebd3642406992a","https://git.kernel.org/stable/c/9989e0ca7462c62f93dbc62f684448aa2efb9226"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39784","score":0.0013,"percentile":0.02633,"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."]}