{"id":"CVE-2023-53123","title":"PCI: s390: Fix use-after-free of PCI resources with per-function hotplug","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nPCI: s390: Fix use-after-free of PCI resources with per-function hotplug\n\nOn s390 PCI functions may be hotplugged individually even when they\nbelong to a multi-function…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 < 437bb839e36cc9f35adc6d2a2bf113b7a0fc9985","Linux >= a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 < a2410d0c3d2d714ed968a135dfcbed6aa3ff7027","Linux >= a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 < b99ebf4b62774e690e73a551cf5fbf6f219bdd96","Linux >= a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 < ab909509850b27fd39b8ba99e44cda39dbc3858c","Linux 5.13"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-05T20:18:15.332876Z"},"published":"2025-05-02","updated":"2026-11-05","sourceUpdated":"2026-11-05T20:21:03.067Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-53123","references":[{"url":"https://git.kernel.org/stable/c/437bb839e36cc9f35adc6d2a2bf113b7a0fc9985"},{"url":"https://git.kernel.org/stable/c/a2410d0c3d2d714ed968a135dfcbed6aa3ff7027"},{"url":"https://git.kernel.org/stable/c/b99ebf4b62774e690e73a551cf5fbf6f219bdd96"},{"url":"https://git.kernel.org/stable/c/ab909509850b27fd39b8ba99e44cda39dbc3858c"}],"tags":["cve.org"],"epss":0.00192,"epssPercentile":0.08943,"ingestedAt":"2026-11-05T22:38:31.774Z","slug":"CVE-2023-53123","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nPCI: s390: Fix use-after-free of PCI resources with per-function hotplug\n\nOn s390 PCI functions may be hotplugged individually even when they\nbelong to a multi-function device. In particular on an SR-IOV device VFs\nmay be removed and later re-added.\n\nIn commit a50297cf8235 (\"s390/pci: separate zbus creation from\nscanning\") it was missed however that struct pci_bus and struct\nzpci_bus's resource list retained a reference to the PCI functions MMIO\nresources even though those resources are released and freed on\nhot-unplug. These stale resources may subsequently be claimed when the\nPCI function re-appears resulting in use-after-free.\n\nOne idea of fixing this use-after-free in s390 specific code that was\ninvestigated was to simply keep resources around from the moment a PCI\nfunction first appeared until the whole virtual PCI bus created for\na multi-function device disappears. The problem with this however is\nthat due to the requirement of artificial MMIO addreesses (address\ncookies) extra logic is then needed to keep the address cookies\ncompatible on re-plug. At the same time the MMIO resources semantically\nbelong to the PCI function so tying their lifecycle to the function\nseems more logical.\n\nInstead a simpler approach is to remove the resources of an individually\nhot-unplugged PCI function from the PCI bus's resource list while\nkeeping the resources of other PCI functions on the PCI bus untouched.\n\nThis is done by introducing pci_bus_remove_resource() to remove an\nindividual resource. Similarly the resource also needs to be removed\nfrom the struct zpci_bus's resource list. It turns out however, that\nthere is really no need to add the MMIO resources to the struct\nzpci_bus's resource list at all and instead we can simply use the\nzpci_bar_struct's resource pointer directly.\n\n## Affected\n\n- `Linux >= a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 < 437bb839e36cc9f35adc6d2a2bf113b7a0fc9985`\n- `Linux >= a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 < a2410d0c3d2d714ed968a135dfcbed6aa3ff7027`\n- `Linux >= a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 < b99ebf4b62774e690e73a551cf5fbf6f219bdd96`\n- `Linux >= a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 < ab909509850b27fd39b8ba99e44cda39dbc3858c`\n- `Linux 5.13`\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":[]}