Categories
CVE-2025-21804 high CVSS 7.1

Vulnerability in Linux kernel (CVE-2025-21804)

Summary

Vulnerability in Linux kernel (CVE-2025-21804). Confidential information can be exposed externally.

Original description

The description as published by the source.

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]

Source: NIST National Vulnerability Database NVD

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2025-21804 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-21804" on the vendor's site.

CVE-2025-21804 (Linux kernel) — CWE-476 / CVSS v3 7.1
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-476) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。

  2. 2
    Post-deployment verification verify
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Linux Kernel
[{"type":"ECOSYSTEM","events":[{"introduced":"5.8.0"},{"fixed":"5.10.235"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.179"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.129"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.76"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.13"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.13.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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