Vulnerability-Lookup

FKIE_CVE-2025-39904

Vulnerability from fkie_nvd - Published: 2025-10-01 08:15 - Updated: 2026-06-17 09:18

Severity

5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: arm64: kexec: initialize kexec_buf struct in load_other_segments() Patch series "kexec: Fix invalid field access". The kexec_buf structure was previously declared without initialization. commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly") added a field that is always read but not consistently populated by all architectures. This un-initialized field will contain garbage. This is also triggering a UBSAN warning when the uninitialized data was accessed: ------------[ cut here ]------------ UBSAN: invalid-load in ./include/linux/kexec.h:210:10 load of value 252 is not a valid value for type '_Bool' Zero-initializing kexec_buf at declaration ensures all fields are cleanly set, preventing future instances of uninitialized memory being used. An initial fix was already landed for arm64[0], and this patchset fixes the problem on the remaining arm64 code and on riscv, as raised by Mark. Discussions about this problem could be found at[1][2]. This patch (of 3): The kexec_buf structure was previously declared without initialization. commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly") added a field that is always read but not consistently populated by all architectures. This un-initialized field will contain garbage. This is also triggering a UBSAN warning when the uninitialized data was accessed: ------------[ cut here ]------------ UBSAN: invalid-load in ./include/linux/kexec.h:210:10 load of value 252 is not a valid value for type '_Bool' Zero-initializing kexec_buf at declaration ensures all fields are cleanly set, preventing future instances of uninitialized memory being used.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/04d3cd43700a2d0fe4bfb1012a8ec7f2e34a3507	Patch
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/340cc9a3bd30b25edaf6a9708d41b5f2c10a054a	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	6.17
linux	linux_kernel	6.17
linux	linux_kernel	6.17
linux	linux_kernel	6.17
linux	linux_kernel	6.17

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kernel/machine_kexec_file.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "versionType": "git"
            },
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              "version": "bf454ec31add6790f6cdc88328e38901fcbbade6",
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            }
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        },
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              "version": "6.16"
            },
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              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.16.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: kexec: initialize kexec_buf struct in load_other_segments()\n\nPatch series \"kexec: Fix invalid field access\".\n\nThe kexec_buf structure was previously declared without initialization. \ncommit bf454ec31add (\"kexec_file: allow to place kexec_buf randomly\")\nadded a field that is always read but not consistently populated by all\narchitectures.  This un-initialized field will contain garbage.\n\nThis is also triggering a UBSAN warning when the uninitialized data was\naccessed:\n\n\t------------[ cut here ]------------\n\tUBSAN: invalid-load in ./include/linux/kexec.h:210:10\n\tload of value 252 is not a valid value for type \u0027_Bool\u0027\n\nZero-initializing kexec_buf at declaration ensures all fields are cleanly\nset, preventing future instances of uninitialized memory being used.\n\nAn initial fix was already landed for arm64[0], and this patchset fixes\nthe problem on the remaining arm64 code and on riscv, as raised by Mark.\n\nDiscussions about this problem could be found at[1][2].\n\n\nThis patch (of 3):\n\nThe kexec_buf structure was previously declared without initialization.\ncommit bf454ec31add (\"kexec_file: allow to place kexec_buf randomly\")\nadded a field that is always read but not consistently populated by all\narchitectures. This un-initialized field will contain garbage.\n\nThis is also triggering a UBSAN warning when the uninitialized data was\naccessed:\n\n\t------------[ cut here ]------------\n\tUBSAN: invalid-load in ./include/linux/kexec.h:210:10\n\tload of value 252 is not a valid value for type \u0027_Bool\u0027\n\nZero-initializing kexec_buf at declaration ensures all fields are\ncleanly set, preventing future instances of uninitialized memory being\nused."
    }
  ],
  "id": "CVE-2025-39904",
  "lastModified": "2026-06-17T09:18:47.620",
  "metrics": {
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        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
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          "role": "CISA Coordinator",
          "timestamp": "2026-01-14T19:30:11.300750Z",
          "version": "2.0.3"
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  "published": "2025-10-01T08:15:33.250",
  "references": [
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      "tags": [
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    },
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
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        {
          "lang": "en",
          "value": "CWE-908"
        }
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      "source": "nvd@nist.gov",
      "type": "Primary"
    },
    {
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      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}

CVE-2025-39904 (GCVE-0-2025-39904)

Vulnerability from cvelistv5 – Published: 2025-10-01 07:44 – Updated: 2026-05-11 21:38

Title

arm64: kexec: initialize kexec_buf struct in load_other_segments()

Summary

Severity

5.5 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-01-14 19:30 UTC

CWE

CWE-908 - Use of Uninitialized Resource

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6665 records in the last 180 days details

References

2 references

URL	Tags
https://git.kernel.org/stable/c/340cc9a3bd30b25ed…
https://git.kernel.org/stable/c/04d3cd43700a2d0fe…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: bf454ec31add6790f6cdc88328e38901fcbbade6 , < 340cc9a3bd30b25edaf6a9708d41b5f2c10a054a (git) Affected: bf454ec31add6790f6cdc88328e38901fcbbade6 , < 04d3cd43700a2d0fe4bfb1012a8ec7f2e34a3507 (git)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.16.8 , ≤ 6.16.* (semver) Unaffected: 6.17 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

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              "attackVector": "LOCAL",
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              "confidentialityImpact": "NONE",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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