CVE-2026-43278 (GCVE-0-2026-43278)
Vulnerability from cvelistv5
Published
2026-05-06 11:29
Modified
2026-08-05 12:27
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: dm: clear cloned request bio pointer when last clone bio completes Stale rq->bio values have been observed to cause double-initialization of cloned bios in request-based device-mapper targets, leading to use-after-free and double-free scenarios. One such case occurs when using dm-multipath on top of a PCIe NVMe namespace, where cloned request bios are freed during blk_complete_request(), but rq->bio is left intact. Subsequent clone teardown then attempts to free the same bios again via blk_rq_unprep_clone(). The resulting double-free path looks like: nvme_pci_complete_batch() nvme_complete_batch() blk_mq_end_request_batch() blk_complete_request() // called on a DM clone request bio_endio() // first free of all clone bios ... rq->end_io() // end_clone_request() dm_complete_request(tio->orig) dm_softirq_done() dm_done() dm_end_request() blk_rq_unprep_clone() // second free of clone bios Fix this by clearing the clone request's bio pointer when the last cloned bio completes, ensuring that later teardown paths do not attempt to free already-released bios.
References
Impacted products
Vendor Product Version
Linux Linux Version: ab3e1d3bbab9e973aeb4dd4603251578658a47ff
Version: ab3e1d3bbab9e973aeb4dd4603251578658a47ff
Version: ab3e1d3bbab9e973aeb4dd4603251578658a47ff
Version: ab3e1d3bbab9e973aeb4dd4603251578658a47ff
Version: ab3e1d3bbab9e973aeb4dd4603251578658a47ff
Version: ab3e1d3bbab9e973aeb4dd4603251578658a47ff
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/dm-rq.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/dm-rq.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.1"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.165",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.128",
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            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.165",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.128",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.75",
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                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm: clear cloned request bio pointer when last clone bio completes\n\nStale rq-\u003ebio values have been observed to cause double-initialization of\ncloned bios in request-based device-mapper targets, leading to\nuse-after-free and double-free scenarios.\n\nOne such case occurs when using dm-multipath on top of a PCIe NVMe\nnamespace, where cloned request bios are freed during\nblk_complete_request(), but rq-\u003ebio is left intact. Subsequent clone\nteardown then attempts to free the same bios again via\nblk_rq_unprep_clone().\n\nThe resulting double-free path looks like:\n\n  nvme_pci_complete_batch()\n    nvme_complete_batch()\n      blk_mq_end_request_batch()\n        blk_complete_request()        // called on a DM clone request\n          bio_endio()                 // first free of all clone bios\n          ...\n        rq-\u003eend_io()                  // end_clone_request()\n          dm_complete_request(tio-\u003eorig)\n            dm_softirq_done()\n              dm_done()\n                dm_end_request()\n                  blk_rq_unprep_clone()  // second free of clone bios\n\nFix this by clearing the clone request\u0027s bio pointer when the last cloned\nbio completes, ensuring that later teardown paths do not attempt to free\nalready-released bios."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable request-based device-mapper path is reached by local block I/O, such as reads or writes to a filesystem backed by dm-multipath. It is not itself a network protocol handler, even though network services may indirectly generate disk I/O.\nAC:L - On an affected request-based dm-multipath stack over blk-mq/NVMe, ordinary I/O can drive the deterministic completion path that frees the clone bios and then tears down the clone. No attacker-uncontrolled race is required.\nPR:L - Creating or reconfiguring DM devices requires CAP_SYS_ADMIN, but triggering the bug only requires the ability to issue I/O to an existing affected mapped device, for example through files the local user can read or write. Thus a basic unprivileged local user can reach the vulnerable path.\nUI:N - The attacker can trigger the I/O directly through their own syscalls. No separate victim action is required.\nS:U - The impact remains within the kernel/host security authority. This is a standard local kernel memory-corruption issue, not a VM escape or cross-authority boundary bypass.\nC:H - The stale cloned bio pointer causes use-after-free/double-free of kernel heap objects from the DM bioset. Per kernel CVSS guidance, such memory corruption is treated as capable of enabling high-impact information disclosure.\nI:H - The double-free/use-after-free can corrupt allocator state or allow overlapping/reused kernel objects, which is defensibly exploitable for arbitrary memory modification or code execution. Per guidance, UAF/double-free memory corruption warrants high integrity impact.\nA:H - Even without full exploitation, the double-free/use-after-free can trigger kernel memory corruption, oops, or panic during I/O completion. Repeated attacker-controlled I/O can repeatedly hit the vulnerable path."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:27:00.162Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8d9ddad561136f7e6a9346767bf97b4d79e38e67"
        },
        {
          "url": "https://git.kernel.org/stable/c/7daf279c674d515fb22a727a7bbc92aeb35c5442"
        },
        {
          "url": "https://git.kernel.org/stable/c/e2e738e8dfbbf83bd2bae0467ec4420cc52da42a"
        },
        {
          "url": "https://git.kernel.org/stable/c/b1c1a2637ebd675aa2d71fee8c70da8791d73850"
        },
        {
          "url": "https://git.kernel.org/stable/c/83d72091804600ead96dc9e9f518ea56cb4942f6"
        },
        {
          "url": "https://git.kernel.org/stable/c/fb8a6c18fb9a6561f7a15b58b272442b77a242dd"
        }
      ],
      "title": "dm: clear cloned request bio pointer when last clone bio completes",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43278",
    "datePublished": "2026-05-06T11:29:00.193Z",
    "dateReserved": "2026-05-01T14:12:55.998Z",
    "dateUpdated": "2026-08-05T12:27:00.162Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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