{"id":"CVE-2025-39784","title":"PCI: Fix link speed calculation on retrain failure","summary":"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 calcula…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 < 16557320f378262b5c605b15edebd3642406992a","Linux >= de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 < 9989e0ca7462c62f93dbc62f684448aa2efb9226","Linux 6.13"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-05T21:11:28.690357Z"},"published":"2025-09-11","updated":"2026-11-05","sourceUpdated":"2026-11-05T21:12:58.115Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-39784","references":[{"url":"https://git.kernel.org/stable/c/16557320f378262b5c605b15edebd3642406992a"},{"url":"https://git.kernel.org/stable/c/9989e0ca7462c62f93dbc62f684448aa2efb9226"}],"tags":["cve.org"],"epss":0.0013,"epssPercentile":0.02675,"ingestedAt":"2026-11-05T22:38:32.027Z","slug":"CVE-2025-39784","body":"## Overview\n\nIn 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]\n\n## Affected\n\n- `Linux >= de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 < 16557320f378262b5c605b15edebd3642406992a`\n- `Linux >= de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 < 9989e0ca7462c62f93dbc62f684448aa2efb9226`\n- `Linux 6.13`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}