GHSA-5WFV-MPG7-6VCR

Vulnerability from github – Published: 2026-07-27 09:31 – Updated: 2026-10-19 21:35
VLAI
Details

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
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-64535"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-415"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-27T08:16:22Z",
    "severity": "CRITICAL"
  },
  "details": "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": "GHSA-5wfv-mpg7-6vcr",
  "modified": "2026-10-19T21:35:39Z",
  "published": "2026-07-27T09:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64535"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/088ee46c18d99baef453afd74181dd40ade044ad"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6f9442983a3e4227afd1c83a5251ddbca585ea21"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7e558308eba14c8136cb1e615f0c850f76d1fc0a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/96fe2513df590e74b04253a45089cae75569570e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dbbd07d0a7020b80f6a7028e561908f7b83b3d5a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dfb902462bca478f050224ec7a7195aafa7643b1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e091ff83d962f9ed00d9bd70443676de9fe98bdc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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