CVE-2023-53363
BaseFortify
Publication date: 2025-09-17
Last updated on: 2025-12-12
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | From 6.2 (inc) to 6.2.12 (exc) |
| linux | linux_kernel | 6.3 |
| linux | linux_kernel | 6.3 |
| linux | linux_kernel | 6.3 |
| linux | linux_kernel | 6.3 |
| linux | linux_kernel | 6.3 |
| linux | linux_kernel | 6.3 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a use-after-free bug in the Linux kernel's PCI subsystem. Specifically, it occurs in the pci_bus_release_domain_nr() function, where the code accesses a pci_bus structure after it has already been freed during bus removal cleanup. This happens because pci_remove_root_bus() calls pci_remove_bus(), which frees the pci_bus struct, and then pci_bus_release_domain_nr() is called and tries to access the freed memory. The bug was introduced by a commit that changed how PCI domain IDs are assigned. The issue was detected by the kernel's kfence tool and fixed by reordering the calls to avoid accessing freed memory.
How can this vulnerability impact me? :
This use-after-free vulnerability can lead to undefined behavior in the kernel, such as crashes or memory corruption. This can cause system instability or denial of service. In some cases, it might be exploitable to escalate privileges or execute arbitrary code within the kernel, depending on the context and attacker capabilities.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring kernel logs for use-after-free errors related to pci_bus_release_domain_nr(). Specifically, look for KFENCE bug messages indicating use-after-free reads in pci_bus_release_domain_nr. You can check the kernel log using the command: dmesg | grep -i 'KFENCE.*pci_bus_release_domain_nr'. Additionally, enabling KFENCE (Kernel Electric Fence) debugging in the kernel can help detect such use-after-free bugs during runtime.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation involves updating the Linux kernel to a version that includes the fix for this use-after-free bug in pci_bus_release_domain_nr(). The fix involves reordering calls in pci_remove_root_bus() to avoid accessing freed memory. Until an updated kernel is applied, monitoring for related kernel errors and avoiding operations that trigger PCI bus removal may reduce exposure.