Vulnerability-Lookup

CVE-2026-89968 (GCVE-0-2026-89968)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:32 – Updated: 2026-09-16 14:40

Title

nvmet-tcp: reject unsolicited H2CData PDUs

Summary

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: reject unsolicited H2CData PDUs nvmet_tcp_handle_h2c_data_pdu() accepts an H2CData PDU after only checking that its TTAG is a valid in-range command index and that the command's data buffers are mapped. It never checks that the target has actually solicited that data by sending an R2T for the command. A remote host can abuse this. It submits a write command that takes the R2T path and, before the target transmits the R2T, sends an H2CData PDU for that command's tag. The data completes the command early, and when the command then fails synchronously (e.g. a length mismatch caught by nvmet_check_transfer_len()), it is completed a second time. Each completion calls nvmet_tcp_queue_response(), so the same command is added to queue->resp_list twice while it is still linked; the second llist_add() makes the node point to itself (lentry->next == lentry). nvmet_tcp_process_resp_list() then walks that self-referential node and adds the command to resp_send_list twice. With CONFIG_DEBUG_LIST this trips the "list_add double add" check (kernel BUG); without it the loop never terminates and the nvmet_tcp workqueue wedges (soft-lockup). It is remotely triggerable and needs no authentication on an allow_any_host subsystem. Track whether an R2T has been transmitted for a command and reject an H2CData PDU that arrives before it. The flag is cleared on command reuse (nvmet_tcp_get_cmd() zeroes cmd->flags) and stays set across the multiple H2CData PDUs of a single solicited transfer.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/02341ee424fb2eed1…
https://git.kernel.org/stable/c/cade124c06f8e738e…
https://git.kernel.org/stable/c/14beef7d4f123fb45…
https://git.kernel.org/stable/c/9fb527103e53fd43a…
https://git.kernel.org/stable/c/2b71f9193e3d3a352…
https://git.kernel.org/stable/c/cf1484d9a75de6809…
https://git.kernel.org/stable/c/1cbed7538946c99e5…
https://git.kernel.org/stable/c/db62b35cbca052860…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: 872d26a391da92ed8f0c0f5cb5fef428067b7f30 , < 02341ee424fb2eed16b5b8a9d247492e49335c21 (git) Affected: 872d26a391da92ed8f0c0f5cb5fef428067b7f30 , < cade124c06f8e738e3a0df285ed2e08953e6bfaa (git) Affected: 872d26a391da92ed8f0c0f5cb5fef428067b7f30 , < 14beef7d4f123fb458fc9844aa74a071871dcca6 (git) Affected: 872d26a391da92ed8f0c0f5cb5fef428067b7f30 , < 9fb527103e53fd43a8e802c2eca407869c204f7a (git) Affected: 872d26a391da92ed8f0c0f5cb5fef428067b7f30 , < 2b71f9193e3d3a352920ba367f1a6db345249038 (git) Affected: 872d26a391da92ed8f0c0f5cb5fef428067b7f30 , < cf1484d9a75de6809ef331e16f525aaa41b0e16d (git) Affected: 872d26a391da92ed8f0c0f5cb5fef428067b7f30 , < 1cbed7538946c99e585acefd11c9ba3a0bdbae05 (git) Affected: 872d26a391da92ed8f0c0f5cb5fef428067b7f30 , < db62b35cbca052860c519cbcabe7650708528738 (git)	guessed
Linux	Linux	Affected: 5.0 Unaffected: 0 , < 5.0 (semver) Unaffected: 5.10.270 , ≤ 5.10.* (semver) Unaffected: 5.15.221 , ≤ 5.15.* (semver) Unaffected: 6.1.188 , ≤ 6.1.* (semver) Unaffected: 6.6.157 , ≤ 6.6.* (semver) Unaffected: 6.12.110 , ≤ 6.12.* (semver) Unaffected: 6.18.51 , ≤ 6.18.* (semver) Unaffected: 7.2.5 , ≤ 7.2.* (semver) Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)	guessed

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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet-tcp: reject unsolicited H2CData PDUs\n\nnvmet_tcp_handle_h2c_data_pdu() accepts an H2CData PDU after only checking\nthat its TTAG is a valid in-range command index and that the command\u0027s\ndata buffers are mapped. It never checks that the target has actually\nsolicited that data by sending an R2T for the command.\n\nA remote host can abuse this. It submits a write command that takes the\nR2T path and, before the target transmits the R2T, sends an H2CData PDU\nfor that command\u0027s tag. The data completes the command early, and when\nthe command then fails synchronously (e.g. a length mismatch caught by\nnvmet_check_transfer_len()), it is completed a second time. Each\ncompletion calls nvmet_tcp_queue_response(), so the same command is added\nto queue-\u003eresp_list twice while it is still linked; the second llist_add()\nmakes the node point to itself (lentry-\u003enext == lentry).\n\nnvmet_tcp_process_resp_list() then walks that self-referential node and\nadds the command to resp_send_list twice. With CONFIG_DEBUG_LIST this\ntrips the \"list_add double add\" check (kernel BUG); without it the loop\nnever terminates and the nvmet_tcp workqueue wedges (soft-lockup). It is\nremotely triggerable and needs no authentication on an allow_any_host\nsubsystem.\n\nTrack whether an R2T has been transmitted for a command and reject an\nH2CData PDU that arrives before it. The flag is cleared on command reuse\n(nvmet_tcp_get_cmd() zeroes cmd-\u003eflags) and stays set across the multiple\nH2CData PDUs of a single solicited transfer."
        }
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            "version": "3.1"
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              "lang": "en",
              "value": "AV:N - nvmet-tcp is an in-kernel NVMe-over-TCP target; after kernel_accept() the receive worker parses CapsuleCmd and H2CData PDUs from a listening TCP portal (typically 4420), so a remote initiator on a cloud or storage node can reach the bug over the network.\nAC:L - The attacker sends a write/Connect CapsuleCmd that queues an R2T, then an H2CData PDU for that tag in the same TCP burst; nvmet_tcp_io_work() receives before it sends, so both PDUs are handled before R2T is transmitted, with no condition outside attacker control.\nPR:N - On the unconnected queue after ICReq, Connect with a non-inline SGL takes the R2T path, H2CData is bound to queue-\u003econnect while nr_cmds is 0, and nvmet_check_transfer_len() runs before host-NQN allow-list or DH-HMAC-CHAP, so no credentials or Linux privileges are required.\nUI:N - Exploitation uses only attacker-sent NVMe/TCP PDUs against an already listening target; no victim action such as mounting a device or opening a file is required.\nS:U - The corrupted resp_list, workqueue hang, and optional list_add BUG occur inside the target host kernel\u0027s NVMe/TCP worker and do not cross a VM, IOMMU, or other security authority.\nC:N - Double llist_add makes the command node self-referential and then livelocks or hits DEBUG_LIST checks; there is no use-after-free, out-of-bounds read, or other primitive that discloses kernel memory.\nI:N - The second llist_add only points the node at itself rather than creating an attacker-controlled write; there is no use-after-free, OOB write, or type confusion that would allow arbitrary kernel modification or code execution.\nA:H - nvmet_tcp_process_resp_list() walks the self-loop forever, wedging WQ_MEM_RECLAIM nvmet_tcp_wq in a soft lockup; CONFIG_DEBUG_LIST/BUG_ON_DATA_CORRUPTION can BUG on list_add double add, and cancel_work_sync() during teardown deadlocks as well."
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        },
        {
          "url": "https://git.kernel.org/stable/c/db62b35cbca052860c519cbcabe7650708528738"
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      "title": "nvmet-tcp: reject unsolicited H2CData PDUs",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89968",
    "datePublished": "2026-09-16T10:32:48.852Z",
    "dateReserved": "2026-09-11T19:38:34.778Z",
    "dateUpdated": "2026-09-16T14:40:46.581Z",
    "state": "PUBLISHED"
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The data completes the command early, and when\\nthe command then fails synchronously (e.g. a length mismatch caught by\\nnvmet_check_transfer_len()), it is completed a second time. Each\\ncompletion calls nvmet_tcp_queue_response(), so the same command is added\\nto queue-\u003eresp_list twice while it is still linked; the second llist_add()\\nmakes the node point to itself (lentry-\u003enext == lentry).\\n\\nnvmet_tcp_process_resp_list() then walks that self-referential node and\\nadds the command to resp_send_list twice. With CONFIG_DEBUG_LIST this\\ntrips the \\\"list_add double add\\\" check (kernel BUG); without it the loop\\nnever terminates and the nvmet_tcp workqueue wedges (soft-lockup). It is\\nremotely triggerable and needs no authentication on an allow_any_host\\nsubsystem.\\n\\nTrack whether an R2T has been transmitted for a command and reject an\\nH2CData PDU that arrives before it. The flag is cleared on command reuse\\n(nvmet_tcp_get_cmd() zeroes cmd-\u003eflags) and stays set across the multiple\\nH2CData PDUs of a single solicited transfer.\"}],\"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\":\"872d26a391da92ed8f0c0f5cb5fef428067b7f30\",\"lessThan\":\"02341ee424fb2eed16b5b8a9d247492e49335c21\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"872d26a391da92ed8f0c0f5cb5fef428067b7f30\",\"lessThan\":\"cade124c06f8e738e3a0df285ed2e08953e6bfaa\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"872d26a391da92ed8f0c0f5cb5fef428067b7f30\",\"lessThan\":\"14beef7d4f123fb458fc9844aa74a071871dcca6\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"872d26a391da92ed8f0c0f5cb5fef428067b7f30\",\"lessThan\":\"9fb527103e53fd43a8e802c2eca407869c204f7a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"872d26a391da92ed8f0c0f5cb5fef428067b7f30\",\"lessThan\":\"2b71f9193e3d3a352920ba367f1a6db345249038\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"872d26a391da92ed8f0c0f5cb5fef428067b7f30\",\"lessThan\":\"cf1484d9a75de6809ef331e16f525aaa41b0e16d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"872d26a391da92ed8f0c0f5cb5fef428067b7f30\",\"lessThan\":\"1cbed7538946c99e585acefd11c9ba3a0bdbae05\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"872d26a391da92ed8f0c0f5cb5fef428067b7f30\",\"lessThan\":\"db62b35cbca052860c519cbcabe7650708528738\",\"versionType\":\"git\",\"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\":\"5.0\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.270\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.221\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.188\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.157\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.110\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.51\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.5\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc2\",\"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:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/02341ee424fb2eed16b5b8a9d247492e49335c21\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/14beef7d4f123fb458fc9844aa74a071871dcca6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/1cbed7538946c99e585acefd11c9ba3a0bdbae05\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2b71f9193e3d3a352920ba367f1a6db345249038\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9fb527103e53fd43a8e802c2eca407869c204f7a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cade124c06f8e738e3a0df285ed2e08953e6bfaa\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cf1484d9a75de6809ef331e16f525aaa41b0e16d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/db62b35cbca052860c519cbcabe7650708528738\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

FKIE_CVE-2026-89968

Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-09-16 15:18

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/02341ee424fb2eed16b5b8a9d247492e49335c21
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/14beef7d4f123fb458fc9844aa74a071871dcca6
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/1cbed7538946c99e585acefd11c9ba3a0bdbae05
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2b71f9193e3d3a352920ba367f1a6db345249038
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/9fb527103e53fd43a8e802c2eca407869c204f7a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/cade124c06f8e738e3a0df285ed2e08953e6bfaa
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/cf1484d9a75de6809ef331e16f525aaa41b0e16d
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/db62b35cbca052860c519cbcabe7650708528738

Impacted products

	Vendor	Product	Version

JSON

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": "02341ee424fb2eed16b5b8a9d247492e49335c21",
              "status": "affected",
              "version": "872d26a391da92ed8f0c0f5cb5fef428067b7f30",
              "versionType": "git"
            },
            {
              "lessThan": "cade124c06f8e738e3a0df285ed2e08953e6bfaa",
              "status": "affected",
              "version": "872d26a391da92ed8f0c0f5cb5fef428067b7f30",
              "versionType": "git"
            },
            {
              "lessThan": "14beef7d4f123fb458fc9844aa74a071871dcca6",
              "status": "affected",
              "version": "872d26a391da92ed8f0c0f5cb5fef428067b7f30",
              "versionType": "git"
            },
            {
              "lessThan": "9fb527103e53fd43a8e802c2eca407869c204f7a",
              "status": "affected",
              "version": "872d26a391da92ed8f0c0f5cb5fef428067b7f30",
              "versionType": "git"
            },
            {
              "lessThan": "2b71f9193e3d3a352920ba367f1a6db345249038",
              "status": "affected",
              "version": "872d26a391da92ed8f0c0f5cb5fef428067b7f30",
              "versionType": "git"
            },
            {
              "lessThan": "cf1484d9a75de6809ef331e16f525aaa41b0e16d",
              "status": "affected",
              "version": "872d26a391da92ed8f0c0f5cb5fef428067b7f30",
              "versionType": "git"
            },
            {
              "lessThan": "1cbed7538946c99e585acefd11c9ba3a0bdbae05",
              "status": "affected",
              "version": "872d26a391da92ed8f0c0f5cb5fef428067b7f30",
              "versionType": "git"
            },
            {
              "lessThan": "db62b35cbca052860c519cbcabe7650708528738",
              "status": "affected",
              "version": "872d26a391da92ed8f0c0f5cb5fef428067b7f30",
              "versionType": "git"
            }
          ]
        },
        {
          "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": "5.0"
            },
            {
              "lessThan": "5.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "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: reject unsolicited H2CData PDUs\n\nnvmet_tcp_handle_h2c_data_pdu() accepts an H2CData PDU after only checking\nthat its TTAG is a valid in-range command index and that the command\u0027s\ndata buffers are mapped. It never checks that the target has actually\nsolicited that data by sending an R2T for the command.\n\nA remote host can abuse this. It submits a write command that takes the\nR2T path and, before the target transmits the R2T, sends an H2CData PDU\nfor that command\u0027s tag. The data completes the command early, and when\nthe command then fails synchronously (e.g. a length mismatch caught by\nnvmet_check_transfer_len()), it is completed a second time. Each\ncompletion calls nvmet_tcp_queue_response(), so the same command is added\nto queue-\u003eresp_list twice while it is still linked; the second llist_add()\nmakes the node point to itself (lentry-\u003enext == lentry).\n\nnvmet_tcp_process_resp_list() then walks that self-referential node and\nadds the command to resp_send_list twice. With CONFIG_DEBUG_LIST this\ntrips the \"list_add double add\" check (kernel BUG); without it the loop\nnever terminates and the nvmet_tcp workqueue wedges (soft-lockup). It is\nremotely triggerable and needs no authentication on an allow_any_host\nsubsystem.\n\nTrack whether an R2T has been transmitted for a command and reject an\nH2CData PDU that arrives before it. The flag is cleared on command reuse\n(nvmet_tcp_get_cmd() zeroes cmd-\u003eflags) and stays set across the multiple\nH2CData PDUs of a single solicited transfer."
    }
  ],
  "id": "CVE-2026-89968",
  "lastModified": "2026-09-16T15:18:21.090",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-16T11:17:07.387",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/02341ee424fb2eed16b5b8a9d247492e49335c21"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/14beef7d4f123fb458fc9844aa74a071871dcca6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1cbed7538946c99e585acefd11c9ba3a0bdbae05"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2b71f9193e3d3a352920ba367f1a6db345249038"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9fb527103e53fd43a8e802c2eca407869c204f7a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cade124c06f8e738e3a0df285ed2e08953e6bfaa"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cf1484d9a75de6809ef331e16f525aaa41b0e16d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/db62b35cbca052860c519cbcabe7650708528738"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-46H3-R5W2-2VQQ

Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 15:31

Details

In the Linux kernel, the following vulnerability has been resolved:

nvmet-tcp: reject unsolicited H2CData PDUs

nvmet_tcp_handle_h2c_data_pdu() accepts an H2CData PDU after only checking that its TTAG is a valid in-range command index and that the command's data buffers are mapped. It never checks that the target has actually solicited that data by sending an R2T for the command.

A remote host can abuse this. It submits a write command that takes the R2T path and, before the target transmits the R2T, sends an H2CData PDU for that command's tag. The data completes the command early, and when the command then fails synchronously (e.g. a length mismatch caught by nvmet_check_transfer_len()), it is completed a second time. Each completion calls nvmet_tcp_queue_response(), so the same command is added to queue->resp_list twice while it is still linked; the second llist_add() makes the node point to itself (lentry->next == lentry).

nvmet_tcp_process_resp_list() then walks that self-referential node and adds the command to resp_send_list twice. With CONFIG_DEBUG_LIST this trips the "list_add double add" check (kernel BUG); without it the loop never terminates and the nvmet_tcp workqueue wedges (soft-lockup). It is remotely triggerable and needs no authentication on an allow_any_host subsystem.

Track whether an R2T has been transmitted for a command and reject an H2CData PDU that arrives before it. The flag is cleared on command reuse (nvmet_tcp_get_cmd() zeroes cmd->flags) and stays set across the multiple H2CData PDUs of a single solicited transfer.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-89968"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T11:17:07Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet-tcp: reject unsolicited H2CData PDUs\n\nnvmet_tcp_handle_h2c_data_pdu() accepts an H2CData PDU after only checking\nthat its TTAG is a valid in-range command index and that the command\u0027s\ndata buffers are mapped. It never checks that the target has actually\nsolicited that data by sending an R2T for the command.\n\nA remote host can abuse this. It submits a write command that takes the\nR2T path and, before the target transmits the R2T, sends an H2CData PDU\nfor that command\u0027s tag. The data completes the command early, and when\nthe command then fails synchronously (e.g. a length mismatch caught by\nnvmet_check_transfer_len()), it is completed a second time. Each\ncompletion calls nvmet_tcp_queue_response(), so the same command is added\nto queue-\u003eresp_list twice while it is still linked; the second llist_add()\nmakes the node point to itself (lentry-\u003enext == lentry).\n\nnvmet_tcp_process_resp_list() then walks that self-referential node and\nadds the command to resp_send_list twice. With CONFIG_DEBUG_LIST this\ntrips the \"list_add double add\" check (kernel BUG); without it the loop\nnever terminates and the nvmet_tcp workqueue wedges (soft-lockup). It is\nremotely triggerable and needs no authentication on an allow_any_host\nsubsystem.\n\nTrack whether an R2T has been transmitted for a command and reject an\nH2CData PDU that arrives before it. The flag is cleared on command reuse\n(nvmet_tcp_get_cmd() zeroes cmd-\u003eflags) and stays set across the multiple\nH2CData PDUs of a single solicited transfer.",
  "id": "GHSA-46h3-r5w2-2vqq",
  "modified": "2026-09-16T15:31:03Z",
  "published": "2026-09-16T12:30:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89968"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/02341ee424fb2eed16b5b8a9d247492e49335c21"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/14beef7d4f123fb458fc9844aa74a071871dcca6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1cbed7538946c99e585acefd11c9ba3a0bdbae05"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b71f9193e3d3a352920ba367f1a6db345249038"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9fb527103e53fd43a8e802c2eca407869c204f7a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cade124c06f8e738e3a0df285ed2e08953e6bfaa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf1484d9a75de6809ef331e16f525aaa41b0e16d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/db62b35cbca052860c519cbcabe7650708528738"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-89968 (GCVE-0-2026-89968)

FKIE_CVE-2026-89968

GHSA-46H3-R5W2-2VQQ

Tags

Sightings

Nomenclature

Related by attack behaviour