CVE-2025-21804

Kernel-memory disclosure or crash via dangling resource name

Published Feb 27, 2025 · Updated Aug 5, 2026

Memory-safety failure in Linux kernel R-Car PCIe endpoint support allows local users to disclose kernel memory or crash the system. rcar_pcie_parse_outbound_ranges() passes the stack-backed outbound_name buffer to devm_request_mem_region(), leaving resource entries with a dangling name pointer after the function returns. Reading the world-readable /proc/iomem on an affected R-Car endpoint dereferences that pointer, exposing stale stack data or overrunning into unmapped memory and crashing the kernel.

CVSS severity7.1
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory-safety failure in Linux kernel R-Car PCIe endpoint support allows local users to disclose kernel memory or crash the system. rcar_pcie_parse_outbound_ranges() passes the stack-backed outbound_name buffer to devm_request_mem_region(), leaving resource entries with a dangling name pointer after the function returns. Reading the world-readable /proc/iomem on an affected R-Car endpoint dereferences that pointer, exposing stale stack data or overrunning into unmapped memory and crashing the kernel.

The record

CVE
CVE-2025-21804
Published
Feb 27, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2a6d0d63d99956a66f6605832f11755d74a41951 <24576899c49509c0d533bcf569139f691d8f7af7
  2. Affected versionversion=2a6d0d63d99956a66f6605832f11755d74a41951 <2c54b9fca1755e80a343ccfde0652dc5ea4744b2
  3. Affected versionversion=2a6d0d63d99956a66f6605832f11755d74a41951 <2d2da5a4c1b4509f6f7e5a8db015cd420144beb4
  4. Affected versionversion=2a6d0d63d99956a66f6605832f11755d74a41951 <44708208c2a4b828a57a2abe7799c9d3962e7eaa
  5. Affected versionversion=2a6d0d63d99956a66f6605832f11755d74a41951 <6987e021b64cbb49981d140bb72d9d1466f191c4
  6. Affected versionversion=2a6d0d63d99956a66f6605832f11755d74a41951 <7a47e14c5fb0b6dba7073be7b0119fb8fe864e01
  7. Affected versionversion=2a6d0d63d99956a66f6605832f11755d74a41951 <9ff46b0bfeb6e0724a4ace015aa7a0b887cdb7c1
  8. Affected versionversion=5.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2a6d0d63d99956a66f6605832f11755d74a41951 <24576899c49509c0d533bcf569139f691d8f7af7; version=2a6d0d63d99956a66f6605832f11755d74a41951 <2c54b9fca1755e80a343ccfde0652dc5ea4744b2; version=2a6d0d63d99956a66f6605832f11755d74a41951 <2d2da5a4c1b4509f6f7e5a8db015cd420144beb4; version=2a6d0d63d99956a66f6605832f11755d74a41951 <44708208c2a4b828a57a2abe7799c9d3962e7eaa; version=2a6d0d63d99956a66f6605832f11755d74a41951 <6987e021b64cbb49981d140bb72d9d1466f191c4; version=2a6d0d63d99956a66f6605832f11755d74a41951 <7a47e14c5fb0b6dba7073be7b0119fb8fe864e01; version=2a6d0d63d99956a66f6605832f11755d74a41951 <9ff46b0bfeb6e0724a4ace015aa7a0b887cdb7c1; version=5.8

Published CVSS scores

3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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