CVE-2023-53446: PCI/ASPM: Disable ASPM on MFD function removal to avoid use-after-free

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-09-18 · updated 2026-06-17
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: PCI/ASPM: Disable ASPM on MFD function removal to avoid use-after-free Struct pcie_link_state->downstream is a pointer to the pci_dev of function 0. Previously we retained that pointer when removing function 0, and subsequent ASPM policy changes dereferenced it, resulting in a use-after-free warning from KASAN, e.g.: # echo 1 > /sys/bus/pci/devices/0000:03:00.0/remove # echo powersave > /sys/module/pcie_aspm/parameters/policy BUG: KASAN: slab-use-after-free in pcie_config_aspm_link+0x42d/0x500 Call Trace: kasan_report+0xae/0xe0 pcie_config_aspm_link+0x42d/0x500 pcie_aspm_set_policy+0x8e/0x1a0 param_attr_store+0x162/0x2c0 module_attr_store+0x3e/0x80 PCIe spec r6.0, sec 7.5.3.7, recommends that software program the same ASPM Control value in all functions of multi-function devices. Disable ASPM and free the pcie_link_state when any child function is removed so we can discard the dangling pcie_link_state->downstream pointer and maintain the same ASPM Control configuration for all functions. [bhelgaas: commit log and comment]

Affected products

Linux kernel: from 4.11 before 5.4.251; from 5.5 before 5.10.188; from 5.11 before 5.15.121; from 5.16 before 6.1.39; from 6.2 before 6.3.13; from 6.4 before 6.4.4 — fixed in 5.10.188, 5.15.121, 5.4.251, 6.1.39, 6.3.13, 6.4.4

How to fix

Upgrade to a fixed version: Linux kernel 5.10.188, 5.15.121, 5.4.251, 6.1.39. Check the vendor advisory for mitigations.

References

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