CVE-2024-42302

CVE-2024-42302 is a high-severity vulnerability in Debian Debian Linux with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: PCI/DPC: Fix use-after-free on concurrent DPC and hot-removal Keith reports a use-after-free when a DPC event occurs concurrently to hot-removal of the same portion of the hierarchy: The dpc_handler() awaits readiness of the secondary bus below the Downstream Port where the DPC event occurred. To do so, it polls the config space of the first child device on the secondary bus. If that child device is concurrently removed, accesses to its struct pci_dev cause the kernel to oops. That's because pci_bridge_wait_for_secondary_bus() neglects to hold a reference on the child device. Before v6.3, the function was only called on resume from system sleep or on runtime resume. Holding a reference wasn't necessary back then because the pciehp IRQ thread could never run concurrently. (On resume from system sleep, IRQs are not enabled until after the resume_noirq phase. And runtime resume is always awaited before a PCI device is removed.) However starting with v6.3, pci_bridge_wait_for_secondary_bus() is also called on a DPC event. Commit 53b54ad074de ("PCI/DPC: Await readiness of secondary bus after reset"), which introduced that, failed to appreciate that pci_bridge_wait_for_secondary_bus() now needs to hold a reference on the child device because dpc_handler() and pciehp may indeed run concurrently. The commit was backported to v5.10+ stable kernels, so that's the oldest one affected. Add the missing reference acquisition. Abridged stack trace: BUG: unable to handle page fault for address: 00000000091400c0 CPU: 15 PID: 2464 Comm: irq/53-pcie-dpc 6.9.0 RIP: pci_bus_read_config_dword+0x17/0x50 pci_dev_wait() pci_bridge_wait_for_secondary_bus() dpc_reset_link() pcie_do_recovery() dpc_handler()

Frequently asked questions

What is CVE-2024-42302?
In the Linux kernel, the following vulnerability has been resolved: PCI/DPC: Fix use-after-free on concurrent DPC and hot-removal Keith reports a use-after-free when a DPC event occurs concurrently to hot-removal of the same portion of the hierarchy: The dpc_handler() awaits readiness of the secondary bus below the Downstream Port where the DPC event occurred. To do so, it polls the config space of the first child device on the secondary bus. If that child device is concurrently removed, accesses to its struct pci_dev cause the kernel to oops. That's because pci_bridge_wait_for_secondary_bus() neglects to hold a reference on the child device. Before v6.3, the function was only called on resume from system sleep or on runtime resume. Holding a reference wasn't necessary back then because the pciehp IRQ thread could never run concurrently. (On resume from system sleep, IRQs are not enabled until after the resume_noirq phase. And runtime resume is always awaited before a PCI device is removed.) However starting with v6.3, pci_bridge_wait_for_secondary_bus() is also called on a DPC event. Commit 53b54ad074de ("PCI/DPC: Await readiness of secondary bus after reset"), which introduced that, failed to appreciate that pci_bridge_wait_for_secondary_bus() now needs to hold a reference on the child device because dpc_handler() and pciehp may indeed run concurrently. The commit was backported to v5.10+ stable kernels, so that's the oldest one affected. Add the missing reference acquisition. Abridged stack trace: BUG: unable to handle page fault for address: 00000000091400c0 CPU: 15 PID: 2464 Comm: irq/53-pcie-dpc 6.9.0 RIP: pci_bus_read_config_dword+0x17/0x50 pci_dev_wait() pci_bridge_wait_for_secondary_bus() dpc_reset_link() pcie_do_recovery() dpc_handler()
How severe is CVE-2024-42302?
CVE-2024-42302 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2024-42302 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-42302?
CVE-2024-42302 primarily affects Debian Debian Linux. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-42302?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2024-42302 have an EU (EUVD) identifier?
Yes. CVE-2024-42302 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-39525.
When was CVE-2024-42302 published?
CVE-2024-42302 was published on 2024-08-17 and last updated on 2026-06-17.

References

Affected products (2)

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