CVE-2026-64535

Full vulnerability record from the local CVENow database.

Description

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.

Severity

CRITICAL

CVSS score

9.8 (v3.1)

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-07-27 08:16:22.773000

Last modified

2026-10-19 21:17:43.253000

View original CVE JSON

{
  "id": "CVE-2026-64535",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-07-27T08:16:22.773",
  "lastModified": "2026-10-19T21:17:43.253",
  "vulnStatus": "Received",
  "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() — which performs percpu_ref_put() on the\nsubmission queue — but does NOT mark the command as completed. It\ndoes not set cqe->status, 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 < transfer_len and cqe->status == 0). It therefore calls\nnvmet_req_uninit() a second time on the same command — a double\npercpu_ref_put against a single percpu_ref_get."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/nvme/target/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "91edfca6f8b364d60cde3ddefaf7d03ddf35774b",
              "lessThan": "dfb902462bca478f050224ec7a7195aafa7643b1",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "fda871c0ba5d2eed2cd1c881573168129da70058",
              "lessThan": "7e558308eba14c8136cb1e615f0c850f76d1fc0a",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "fda871c0ba5d2eed2cd1c881573168129da70058",
              "lessThan": "96fe2513df590e74b04253a45089cae75569570e",
              "versionType": "git",
              "status": "affected"
            },
            {
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              "versionType": "git",
              "status": "affected"
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              "lessThan": "6f9442983a3e4227afd1c83a5251ddbca585ea21",
              "versionType": "git",
              "status": "affected"
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              "versionType": "git",
              "status": "affected"
            },
            {
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              "lessThan": "dbbd07d0a7020b80f6a7028e561908f7b83b3d5a",
              "versionType": "git",
              "status": "affected"
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            {
              "version": "4b17476d809273617d3317fa0d4ae78aa488d760",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "5.10.20",
              "lessThan": "5.10.265",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "5.11.3",
              "lessThan": "5.12",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "drivers/nvme/target/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "5.12",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "5.12",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.10.265",
              "lessThanOrEqual": "5.10.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.216",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.178",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.145",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.97",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.40",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T15:41:56.047833Z",
          "id": "CVE-2026-64535",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-415"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/088ee46c18d99baef453afd74181dd40ade044ad",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
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    {
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    {
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}