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CVE-2026-64534 (GCVE-0-2026-64534)

Vulnerability from cvelistv5 – Published: 2026-07-27 06:32 – Updated: 2026-08-05 12:42
VLAI
Title
nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path
Summary
In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path In nvmet_tcp_try_recv_ddgst(), when a data digest mismatch is detected, nvmet_req_uninit() is called unconditionally. However, if the command arrived via the nvmet_tcp_handle_req_failure() path, nvmet_req_init() had returned false and percpu_ref_tryget_live() was never executed. The unconditional percpu_ref_put() inside nvmet_req_uninit() then causes a refcount underflow, leading to a WARNING in percpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and eventually a permanent workqueue deadlock. Check cmd->flags & NVMET_TCP_F_INIT_FAILED before calling nvmet_req_uninit(), matching the existing pattern in nvmet_tcp_execute_request().
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 91edfca6f8b364d60cde3ddefaf7d03ddf35774b , < 22ec7a9fe9153d2737ee9b2fa6d2e43a1491decf (git)
Affected: fda871c0ba5d2eed2cd1c881573168129da70058 , < ba35b1c674ca3841c0dfadd698f2c1b3ec542d4e (git)
Affected: fda871c0ba5d2eed2cd1c881573168129da70058 , < c7874dad84b20433c0fe3919f291a762d40de08b (git)
Affected: fda871c0ba5d2eed2cd1c881573168129da70058 , < e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1 (git)
Affected: fda871c0ba5d2eed2cd1c881573168129da70058 , < d306da8833e75f669d93424fd84940236f3850bc (git)
Affected: fda871c0ba5d2eed2cd1c881573168129da70058 , < 2ed3c9d955e8cd6361f130623baa664a75fb345f (git)
Affected: fda871c0ba5d2eed2cd1c881573168129da70058 , < 4606467a75cfc16721937272ed29462a750b60c8 (git)
Affected: 4b17476d809273617d3317fa0d4ae78aa488d760 (git)
Affected: 5.10.20 , < 5.10.261 (semver)
Affected: 5.11.3 , < 5.12 (semver)
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Linux Linux Affected: 5.12
Unaffected: 0 , < 5.12 (semver)
Unaffected: 5.10.261 , ≤ 5.10.* (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path\n\nIn nvmet_tcp_try_recv_ddgst(), when a data digest mismatch is detected,\nnvmet_req_uninit() is called unconditionally. However, if the command\narrived via the nvmet_tcp_handle_req_failure() path, nvmet_req_init()\nhad returned false and percpu_ref_tryget_live() was never executed. The\nunconditional percpu_ref_put() inside nvmet_req_uninit() then causes a\nrefcount underflow, leading to a WARNING in\npercpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and\neventually a permanent workqueue deadlock.\n\nCheck cmd-\u003eflags \u0026 NVMET_TCP_F_INIT_FAILED before calling\nnvmet_req_uninit(), matching the existing pattern in\nnvmet_tcp_execute_request()."
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            "version": "3.1"
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              "value": "AV:N - The vulnerable NVMe/TCP target receive path processes attacker-supplied ICReq, CapsuleCmd, inline payload, and digest data over an Internet-routable TCP connection.\nAC:L - The attacker can negotiate data digests and reliably send a rejected write command with inline data followed by an incorrect digest; no race or condition outside the attacker\u0027s control is required.\nPR:N - A malformed CapsuleCmd can trigger this path before CONNECT, host-NQN ACL evaluation, or DH-HMAC-CHAP authentication, so the remote attacker needs no credentials or privileges.\nUI:N - The target processes the malicious protocol sequence automatically without any victim action.\nS:U - The vulnerable transport and the affected kernel memory, execution, and storage resources belong to the same target-host security authority.\nC:H - The unmatched reference decrement can offset a legitimate in-flight request reference, allowing command structures and SGL pages to be freed while backend I/O still uses them; this UAF can expose arbitrary reused kernel memory.\nI:H - The premature freeing of request structures and I/O pages can let backend operations write through reallocated memory or corrupt completion control state, making arbitrary kernel writes and control-flow hijacking defensible.\nA:H - The basic trigger causes a submission-queue refcount underflow and permanent workqueue deadlock, while UAF variants can crash the kernel; unauthenticated attackers can repeat the trigger across connections."
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    "dateReserved": "2026-07-19T15:36:31.795Z",
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      "product_status:fixed": "1",
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      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64534.json",
      "version": "2"
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The\\nunconditional percpu_ref_put() inside nvmet_req_uninit() then causes a\\nrefcount underflow, leading to a WARNING in\\npercpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and\\neventually a permanent workqueue deadlock.\\n\\nCheck cmd-\u003eflags \u0026 NVMET_TCP_F_INIT_FAILED before calling\\nnvmet_req_uninit(), matching the existing pattern in\\nnvmet_tcp_execute_request().\"}],\"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\":\"22ec7a9fe9153d2737ee9b2fa6d2e43a1491decf\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"fda871c0ba5d2eed2cd1c881573168129da70058\",\"lessThan\":\"ba35b1c674ca3841c0dfadd698f2c1b3ec542d4e\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"fda871c0ba5d2eed2cd1c881573168129da70058\",\"lessThan\":\"c7874dad84b20433c0fe3919f291a762d40de08b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"fda871c0ba5d2eed2cd1c881573168129da70058\",\"lessThan\":\"e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"fda871c0ba5d2eed2cd1c881573168129da70058\",\"lessThan\":\"d306da8833e75f669d93424fd84940236f3850bc\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"fda871c0ba5d2eed2cd1c881573168129da70058\",\"lessThan\":\"2ed3c9d955e8cd6361f130623baa664a75fb345f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"fda871c0ba5d2eed2cd1c881573168129da70058\",\"lessThan\":\"4606467a75cfc16721937272ed29462a750b60c8\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"4b17476d809273617d3317fa0d4ae78aa488d760\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5.10.20\",\"lessThan\":\"5.10.261\",\"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\":\"5.10.261\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.212\",\"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}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/22ec7a9fe9153d2737ee9b2fa6d2e43a1491decf\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2ed3c9d955e8cd6361f130623baa664a75fb345f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4606467a75cfc16721937272ed29462a750b60c8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ba35b1c674ca3841c0dfadd698f2c1b3ec542d4e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c7874dad84b20433c0fe3919f291a762d40de08b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d306da8833e75f669d93424fd84940236f3850bc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-07-30T07:44:55+00:00",
      "cve": "CVE-2026-64534",
      "id": "CVE-2026-64534",
      "initial_release_date": "2026-07-27T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64534.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T01:46:37Z",
      "cve": "CVE-2026-64534",
      "id": "CVE-2026-64534",
      "initial_release_date": "2026-07-27T17:00:01Z",
      "product_status:known_affected": "229",
      "product_status:known_not_affected": "147",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64534",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64534.json",
      "version": "8"
    }
  }
}



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