CVE-2025-21804

CVE-2025-21804 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. 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-476.

Key facts

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]

Frequently asked questions

What is CVE-2025-21804?
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]
How severe is CVE-2025-21804?
CVE-2025-21804 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-21804 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-21804?
CVE-2025-21804 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-21804?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-21804 have an EU (EUVD) identifier?
Yes. CVE-2025-21804 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-5994.
When was CVE-2025-21804 published?
CVE-2025-21804 was published on 2025-02-27 and last updated on 2026-06-17.

References

Affected products (1)

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