FKIE_CVE-2026-64535

Vulnerability from fkie_nvd - Published: 2026-07-27 08:16 - Updated: 2026-08-05 08:16
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: Fix potential UAF when ddgst mismatch Shivam Kumar found via vulnerability testing: When data digest is enabled on an NVMe/TCP connection and a digest mismatch occurs on a non-final H2C_DATA PDU during an R2T-based data transfer, the digest error handler in nvmet_tcp_try_recv_ddgst() calls nvmet_req_uninit() — which performs percpu_ref_put() on the submission queue — but does NOT mark the command as completed. It does not set cqe->status, does not modify rbytes_done, and does not clear any flag. When the subsequent fatal error triggers queue teardown, nvmet_tcp_uninit_data_in_cmds() iterates all commands, checks nvmet_tcp_need_data_in() for each one, and finds that the already-uninited command still appears to need data (because rbytes_done < transfer_len and cqe->status == 0). It therefore calls nvmet_req_uninit() a second time on the same command — a double percpu_ref_put against a single percpu_ref_get.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/088ee46c18d99baef453afd74181dd40ade044ad
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6f9442983a3e4227afd1c83a5251ddbca585ea21
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/96fe2513df590e74b04253a45089cae75569570e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dbbd07d0a7020b80f6a7028e561908f7b83b3d5a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e091ff83d962f9ed00d9bd70443676de9fe98bdc
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/nvme/target/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "96fe2513df590e74b04253a45089cae75569570e",
              "status": "affected",
              "version": "fda871c0ba5d2eed2cd1c881573168129da70058",
              "versionType": "git"
            },
            {
              "lessThan": "e091ff83d962f9ed00d9bd70443676de9fe98bdc",
              "status": "affected",
              "version": "fda871c0ba5d2eed2cd1c881573168129da70058",
              "versionType": "git"
            },
            {
              "lessThan": "6f9442983a3e4227afd1c83a5251ddbca585ea21",
              "status": "affected",
              "version": "fda871c0ba5d2eed2cd1c881573168129da70058",
              "versionType": "git"
            },
            {
              "lessThan": "088ee46c18d99baef453afd74181dd40ade044ad",
              "status": "affected",
              "version": "fda871c0ba5d2eed2cd1c881573168129da70058",
              "versionType": "git"
            },
            {
              "lessThan": "dbbd07d0a7020b80f6a7028e561908f7b83b3d5a",
              "status": "affected",
              "version": "fda871c0ba5d2eed2cd1c881573168129da70058",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "91edfca6f8b364d60cde3ddefaf7d03ddf35774b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4b17476d809273617d3317fa0d4ae78aa488d760",
              "versionType": "git"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.20",
              "versionType": "semver"
            },
            {
              "lessThan": "5.12",
              "status": "affected",
              "version": "5.11.3",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/nvme/target/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.12"
            },
            {
              "lessThan": "5.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet-tcp: Fix potential UAF when ddgst mismatch\n\nShivam Kumar found via vulnerability testing:\nWhen data digest is enabled on an NVMe/TCP connection and a digest\nmismatch occurs on a non-final H2C_DATA PDU during an R2T-based\ndata transfer, the digest error handler in nvmet_tcp_try_recv_ddgst()\ncalls nvmet_req_uninit() \u2014 which performs percpu_ref_put() on the\nsubmission queue \u2014 but does NOT mark the command as completed. It\ndoes not set cqe-\u003estatus, does not modify rbytes_done, and does not\nclear any flag. When the subsequent fatal error triggers queue\nteardown, nvmet_tcp_uninit_data_in_cmds() iterates all commands,\nchecks nvmet_tcp_need_data_in() for each one, and finds that the\nalready-uninited command still appears to need data (because\nrbytes_done \u003c transfer_len and cqe-\u003estatus == 0). It therefore calls\nnvmet_req_uninit() a second time on the same command \u2014 a double\npercpu_ref_put against a single percpu_ref_get."
    }
  ],
  "id": "CVE-2026-64535",
  "lastModified": "2026-08-05T08:16:36.013",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-27T08:16:22.773",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/088ee46c18d99baef453afd74181dd40ade044ad"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6f9442983a3e4227afd1c83a5251ddbca585ea21"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/96fe2513df590e74b04253a45089cae75569570e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dbbd07d0a7020b80f6a7028e561908f7b83b3d5a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e091ff83d962f9ed00d9bd70443676de9fe98bdc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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