Vulnerability-Lookup

FKIE_CVE-2026-64326

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-09-04 14:51

Severity

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: block: skip sync_blockdev() on surprise removal in bdev_mark_dead() bdev_mark_dead()'s @surprise == true means the device is already gone. The filesystem callback fs_bdev_mark_dead() honours this and skips sync_filesystem(), but the bare block device path (no ->mark_dead op) lost its !surprise guard when the holder ->mark_dead callback was wired up (see Fixes), and now calls sync_blockdev() unconditionally, which can hang forever waiting on writeback that can no longer complete. syzkaller hit this via nvme_reset_work()'s "I/O queues lost" path: nvme_mark_namespaces_dead() -> blk_mark_disk_dead() -> bdev_mark_dead(bdev, true) -> sync_blockdev() blocks in folio_wait_writeback(), wedging the reset worker and every task waiting on it. Skip the sync on surprise removal, matching fs_bdev_mark_dead(); invalidate_bdev() still runs. Orderly removal (surprise == false) is unchanged. Found by FuzzNvme(Syzkaller with FEMU fuzzing framework).

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/9818bcae3c0ca1dde4b9a334125c46676e0a9b29	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/aa4c4a9315764b2b7a7182e72cc5ea87520436b4	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d6998ddd507c81e3829489a6ead23f17f5acb7fe	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f41cf35ee2a1e31374b3f54e7579c55153506e70	Patch

Impacted products

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

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "block/bdev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "versionType": "semver"
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              "version": "6.12.96",
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              "status": "unaffected",
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            },
            {
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              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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            },
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: skip sync_blockdev() on surprise removal in bdev_mark_dead()\n\nbdev_mark_dead()\u0027s @surprise == true means the device is already gone.\nThe filesystem callback fs_bdev_mark_dead() honours this and skips\nsync_filesystem(), but the bare block device path (no -\u003emark_dead op)\nlost its !surprise guard when the holder -\u003emark_dead callback was wired\nup (see Fixes), and now calls sync_blockdev() unconditionally, which can\nhang forever waiting on writeback that can no longer complete.\n\nsyzkaller hit this via nvme_reset_work()\u0027s \"I/O queues lost\" path:\nnvme_mark_namespaces_dead() -\u003e blk_mark_disk_dead() -\u003e\nbdev_mark_dead(bdev, true) -\u003e sync_blockdev() blocks in\nfolio_wait_writeback(), wedging the reset worker and every task waiting\non it.\n\nSkip the sync on surprise removal, matching fs_bdev_mark_dead();\ninvalidate_bdev() still runs. Orderly removal (surprise == false) is\nunchanged.\n\nFound by FuzzNvme(Syzkaller with FEMU fuzzing framework)."
    }
  ],
  "id": "CVE-2026-64326",
  "lastModified": "2026-09-04T14:51:12.160",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-07-25T10:17:14.207",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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    },
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
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        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
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      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2026-64326 (GCVE-0-2026-64326)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:49 – Updated: 2026-08-17 04:53

Title

block: skip sync_blockdev() on surprise removal in bdev_mark_dead()

Summary

Severity

No CVSS data available.

Assigner

Linux mitre root

References

5 references

URL	Tags
https://git.kernel.org/stable/c/d6998ddd507c81e38…
https://git.kernel.org/stable/c/f41cf35ee2a1e3137…
https://git.kernel.org/stable/c/9818bcae3c0ca1dde…
https://git.kernel.org/stable/c/aa4c4a9315764b2b7…
https://git.kernel.org/stable/c/49f06cff50a4ccf3b…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: d8530de5a6e82be0ce17a5fdf727a394bcf6444c , < d6998ddd507c81e3829489a6ead23f17f5acb7fe (git) Affected: d8530de5a6e82be0ce17a5fdf727a394bcf6444c , < f41cf35ee2a1e31374b3f54e7579c55153506e70 (git) Affected: d8530de5a6e82be0ce17a5fdf727a394bcf6444c , < 9818bcae3c0ca1dde4b9a334125c46676e0a9b29 (git) Affected: d8530de5a6e82be0ce17a5fdf727a394bcf6444c , < aa4c4a9315764b2b7a7182e72cc5ea87520436b4 (git) Affected: d8530de5a6e82be0ce17a5fdf727a394bcf6444c , < 49f06cff50a4ccf3b7a1a662ceb892b3b21a527a (git)
Linux	Linux	Affected: 6.6 Unaffected: 0 , < 6.6 (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "block/bdev.c"
          ],
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          ],
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              "versionType": "original_commit_for_fix"
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        }
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      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:53:28.310Z",
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        {
          "url": "https://git.kernel.org/stable/c/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a"
        }
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      "title": "block: skip sync_blockdev() on surprise removal in bdev_mark_dead()",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64326",
    "datePublished": "2026-07-25T08:49:54.327Z",
    "dateReserved": "2026-07-19T15:36:31.780Z",
    "dateUpdated": "2026-08-17T04:53:28.310Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

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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FKIE_CVE-2026-64326

CVE-2026-64326 (GCVE-0-2026-64326)

Tags

Sightings

Nomenclature