FKIE_CVE-2022-50530

Vulnerability from fkie_nvd - Published: 2025-10-07 16:15 - Updated: 2026-02-05 15:17
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: blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping() Our syzkaller report a null pointer dereference, root cause is following: __blk_mq_alloc_map_and_rqs set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs blk_mq_alloc_map_and_rqs blk_mq_alloc_rqs // failed due to oom alloc_pages_node // set->tags[hctx_idx] is still NULL blk_mq_free_rqs drv_tags = set->tags[hctx_idx]; // null pointer dereference is triggered blk_mq_clear_rq_mapping(drv_tags, ...) This is because commit 63064be150e4 ("blk-mq: Add blk_mq_alloc_map_and_rqs()") merged the two steps: 1) set->tags[hctx_idx] = blk_mq_alloc_rq_map() 2) blk_mq_alloc_rqs(..., set->tags[hctx_idx]) into one step: set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs() Since tags is not initialized yet in this case, fix the problem by checking if tags is NULL pointer in blk_mq_clear_rq_mapping().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6a440e6d04431e774dc084abe88c106e2a474c1aPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/76dd298094f484c6250ebd076fa53287477b2328Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel 6.1
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "98F5FA4A-A33F-4FAD-894E-FDC9D295742A",
              "versionEndExcluding": "6.0.6",
              "versionStartIncluding": "5.16",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.1:rc1:*:*:*:*:*:*",
              "matchCriteriaId": "E7E331DA-1FB0-4DEC-91AC-7DA69D461C11",
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        }
      ]
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()\n\nOur syzkaller report a null pointer dereference, root cause is\nfollowing:\n\n__blk_mq_alloc_map_and_rqs\n set-\u003etags[hctx_idx] = blk_mq_alloc_map_and_rqs\n  blk_mq_alloc_map_and_rqs\n   blk_mq_alloc_rqs\n    // failed due to oom\n    alloc_pages_node\n    // set-\u003etags[hctx_idx] is still NULL\n    blk_mq_free_rqs\n     drv_tags = set-\u003etags[hctx_idx];\n     // null pointer dereference is triggered\n     blk_mq_clear_rq_mapping(drv_tags, ...)\n\nThis is because commit 63064be150e4 (\"blk-mq:\nAdd blk_mq_alloc_map_and_rqs()\") merged the two steps:\n\n1) set-\u003etags[hctx_idx] = blk_mq_alloc_rq_map()\n2) blk_mq_alloc_rqs(..., set-\u003etags[hctx_idx])\n\ninto one step:\n\nset-\u003etags[hctx_idx] = blk_mq_alloc_map_and_rqs()\n\nSince tags is not initialized yet in this case, fix the problem by\nchecking if tags is NULL pointer in blk_mq_clear_rq_mapping()."
    }
  ],
  "id": "CVE-2022-50530",
  "lastModified": "2026-02-05T15:17:32.020",
  "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": "2025-10-07T16:15:37.020",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/6a440e6d04431e774dc084abe88c106e2a474c1a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      ],
      "url": "https://git.kernel.org/stable/c/76dd298094f484c6250ebd076fa53287477b2328"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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