CVE-2026-64534 (GCVE-0-2026-64534)
Vulnerability from cvelistv5 – Published: 2026-07-27 06:32 – Updated: 2026-08-05 12:42
VLAI
EPSS
VEX
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)
Assigner
References
7 references
Impacted products
2 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) |
guessed | |
| 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 |
{
"containers": {
"cna": {
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{
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"product": "Linux",
"programFiles": [
"drivers/nvme/target/tcp.c"
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],
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"vendor": "Linux",
"versions": [
{
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"version": "5.12"
},
{
"lessThan": "5.12",
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"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
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"versionEndExcluding": "5.10.261",
"versionStartIncluding": "5.10.20",
"vulnerable": true
},
{
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"versionEndExcluding": "5.15.212",
"versionStartIncluding": "5.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.178",
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"vulnerable": true
},
{
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{
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{
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},
{
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"versionStartIncluding": "5.11.3",
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}
],
"negate": false,
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}
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],
"descriptions": [
{
"lang": "en",
"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()."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"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."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-05T12:42:44.214Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/22ec7a9fe9153d2737ee9b2fa6d2e43a1491decf"
},
{
"url": "https://git.kernel.org/stable/c/ba35b1c674ca3841c0dfadd698f2c1b3ec542d4e"
},
{
"url": "https://git.kernel.org/stable/c/c7874dad84b20433c0fe3919f291a762d40de08b"
},
{
"url": "https://git.kernel.org/stable/c/e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1"
},
{
"url": "https://git.kernel.org/stable/c/d306da8833e75f669d93424fd84940236f3850bc"
},
{
"url": "https://git.kernel.org/stable/c/2ed3c9d955e8cd6361f130623baa664a75fb345f"
},
{
"url": "https://git.kernel.org/stable/c/4606467a75cfc16721937272ed29462a750b60c8"
}
],
"title": "nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path",
"x_generator": {
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}
}
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"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2026-64534",
"datePublished": "2026-07-27T06:32:34.301Z",
"dateReserved": "2026-07-19T15:36:31.795Z",
"dateUpdated": "2026-08-05T12:42:44.214Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
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"cve": "CVE-2026-64534",
"date": "2026-09-27",
"epss": "0.00419",
"percentile": "0.33663"
},
"microsoft_vex": {
"current_release_date": "2026-08-14T18:06:41.000Z",
"cve": "CVE-2026-64534",
"id": "msrc_CVE-2026-64534",
"initial_release_date": "2026-08-07T01:16:46.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "1",
"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"
},
"nvd": {
"cve": {
"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": [
{
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"versionType": "git"
},
{
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},
{
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},
{
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"versionType": "git"
},
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"versionType": "git"
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"versionType": "git"
},
{
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"status": "affected",
"version": "5.10.20",
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]
},
{
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"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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},
{
"lessThan": "5.12",
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},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"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: 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()."
}
],
"id": "CVE-2026-64534",
"lastModified": "2026-08-05T08:16:35.860",
"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": "2026-07-27T08:16:22.643",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"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"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Important",
"current_release_date": "2026-09-24T09:31:33+00:00",
"cve": "CVE-2026-64534",
"id": "CVE-2026-64534",
"initial_release_date": "2026-07-27T00:00:00+00:00",
"product_status:fixed": "762",
"product_status:known_affected": "22",
"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": "2026-09-22T16:51:42Z",
"cve": "CVE-2026-64534",
"id": "CVE-2026-64534",
"initial_release_date": "2026-07-27T17:00:01Z",
"product_status:first_fixed": "60",
"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": "9"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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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.
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.
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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.
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