CVE-2025-21850 (GCVE-0-2025-21850)

Vulnerability from cvelistv5 – Published: 2025-03-12 09:42 – Updated: 2026-08-05 11:54
VLAI
Title
nvmet: Fix crash when a namespace is disabled
Summary
In the Linux kernel, the following vulnerability has been resolved: nvmet: Fix crash when a namespace is disabled The namespace percpu counter protects pending I/O, and we can only safely diable the namespace once the counter drop to zero. Otherwise we end up with a crash when running blktests/nvme/058 (eg for loop transport): [ 2352.930426] [ T53909] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI [ 2352.930431] [ T53909] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] [ 2352.930434] [ T53909] CPU: 3 UID: 0 PID: 53909 Comm: kworker/u16:5 Tainted: G W 6.13.0-rc6 #232 [ 2352.930438] [ T53909] Tainted: [W]=WARN [ 2352.930440] [ T53909] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 [ 2352.930443] [ T53909] Workqueue: nvmet-wq nvme_loop_execute_work [nvme_loop] [ 2352.930449] [ T53909] RIP: 0010:blkcg_set_ioprio+0x44/0x180 as the queue is already torn down when calling submit_bio(); So we need to init the percpu counter in nvmet_ns_enable(), and wait for it to drop to zero in nvmet_ns_disable() to avoid having I/O pending after the namespace has been disabled.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 74d16965d7ac378d28ebd833ae6d6a097186a4ec , < cc0607594f6813342b27c752c6fb6f6eb9980cb5 (git)
Affected: 74d16965d7ac378d28ebd833ae6d6a097186a4ec , < 4082326807072b71496501b6a0c55ffe8d5092a5 (git)
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Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (semver)
Unaffected: 6.13.5 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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              "value": "AV:N - The buggy code is in nvmet core, shared by nvmet-tcp (TCP/4420) and nvmet-rdma, and the in-flight request that holds the stale namespace reference is created and timed by a remote NVMe-oF initiator \u2014 `nvmet_req_init()` takes the ref on the command-capsule PDU and the target waits for the host\u0027s H2C data PDUs before executing. The remote peer therefore both holds the reference and picks the moment of the stale dereference.\nAC:L - The attacker can park a write command so the namespace percpu-ref is held indefinitely and then deliver the data PDU at will, so no race must be \"won\" and no memory-layout condition applies; on a loaded target there is always outstanding I/O anyway. In orchestrated NVMe-oF deployments the attacker also drives the disable side through ordinary volume detach, making both halves attacker-controlled.\nPR:N - nvmet performs no cryptographic authentication by default \u2014 admission is a plaintext host-NQN string compare (`nvmet_host_allowed()`) or `allow_any_host=1`, both trivially satisfied by an unauthenticated peer. Issuing normal read/write commands on a connection the attacker establishes requires no privilege on the target host.\nUI:N - In the realistic orchestrated/multi-tenant deployment the attacker triggers the namespace disable itself via a control-plane volume detach while holding stalled I/O, so no other user participates. Namespace disable is also routine automated reconfiguration rather than a discrete victim action.\nS:U - The corruption and its consequences are confined to the target host\u0027s kernel; no VM, IOMMU, or sandbox authority boundary is crossed.\nC:H - This is a use-after-free of `struct file`, the bvec mempool, and PR `pc_ref` slab objects, all reachable from a request whose contents the attacker controls; reclaiming those allocations with attacker-chosen data yields kernel memory disclosure via read/compare responses. Per kernel guidance, UAF is scored High for confidentiality.\nI:H - The file-backed path performs an indirect call through `req-\u003ens-\u003efile-\u003ef_op-\u003ewrite_iter` on a freed file, a direct control-flow-hijack primitive, and the PR path performs a `percpu_ref_put()` write into kfree\u0027d memory. Both are exploitable write/execute primitives after heap grooming.\nA:H - The bug reproduces as an immediate kernel oops \u2014 a general protection fault in `blkcg_set_ioprio()` from `submit_bio()` on a torn-down request queue, as recorded in the fix commit. A remote initiator can trigger this deterministically, panicking the storage target."
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El contador por CPU del espacio de nombres protege la E/S pendiente y solo podemos deshabilitar de forma segura el espacio de nombres una vez que el contador cae a cero. De lo contrario, terminamos con un bloqueo al ejecutar blktests/nvme/058 (por ejemplo, para el transporte de bucle): [2352.930426] [T53909] Ups: error de protecci\u00f3n general, probablemente para la direcci\u00f3n no can\u00f3nica 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI [2352.930431] [T53909] KASAN: null-ptr-deref en el rango [0x0000000000000028-0x000000000000002f] [2352.930434] [T53909] CPU: 3 UID: 0 PID: 53909 Comm: kworker/u16:5 Tainted: GW 6.13.0-rc6 #232 [ 2352.930438] [ T53909] Contaminado: [W]=WARN [ 2352.930440] [ T53909] Nombre del hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 01/04/2014 [ 2352.930443] [ T53909] Cola de trabajo: nvmet-wq nvme_loop_execute_work [nvme_loop] [ 2352.930449] [ T53909] RIP: 0010:blkcg_set_ioprio+0x44/0x180 ya que la cola ya est\u00e1 desactivada al llamar a submit_bio(); Entonces, necesitamos inicializar el contador por CPU en nvmet_ns_enable() y esperar hasta que caiga a cero en nvmet_ns_disable() para evitar 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    "redhat_vex": {
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      "title": "kernel: nvmet: Fix crash when a namespace is disabled",
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      "title": "SUSE CVE CVE-2025-21850",
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    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.5, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2025-21850\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2025-10-01T19:26:16.776927Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-835\", \"description\": \"CWE-835 Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027)\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-10-01T16:58:15.211Z\"}}], \"cna\": {\"title\": \"nvmet: Fix crash when a namespace is disabled\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"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\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:N - The buggy code is in nvmet core, shared by nvmet-tcp (TCP/4420) and nvmet-rdma, and the in-flight request that holds the stale namespace reference is created and timed by a remote NVMe-oF initiator \\u2014 `nvmet_req_init()` takes the ref on the command-capsule PDU and the target waits for the host\u0027s H2C data PDUs before executing. The remote peer therefore both holds the reference and picks the moment of the stale dereference.\\nAC:L - The attacker can park a write command so the namespace percpu-ref is held indefinitely and then deliver the data PDU at will, so no race must be \\\"won\\\" and no memory-layout condition applies; on a loaded target there is always outstanding I/O anyway. In orchestrated NVMe-oF deployments the attacker also drives the disable side through ordinary volume detach, making both halves attacker-controlled.\\nPR:N - nvmet performs no cryptographic authentication by default \\u2014 admission is a plaintext host-NQN string compare (`nvmet_host_allowed()`) or `allow_any_host=1`, both trivially satisfied by an unauthenticated peer. Issuing normal read/write commands on a connection the attacker establishes requires no privilege on the target host.\\nUI:N - In the realistic orchestrated/multi-tenant deployment the attacker triggers the namespace disable itself via a control-plane volume detach while holding stalled I/O, so no other user participates. Namespace disable is also routine automated reconfiguration rather than a discrete victim action.\\nS:U - The corruption and its consequences are confined to the target host\u0027s kernel; no VM, IOMMU, or sandbox authority boundary is crossed.\\nC:H - This is a use-after-free of `struct file`, the bvec mempool, and PR `pc_ref` slab objects, all reachable from a request whose contents the attacker controls; reclaiming those allocations with attacker-chosen data yields kernel memory disclosure via read/compare responses. Per kernel guidance, UAF is scored High for confidentiality.\\nI:H - The file-backed path performs an indirect call through `req-\u003ens-\u003efile-\u003ef_op-\u003ewrite_iter` on a freed file, a direct control-flow-hijack primitive, and the PR path performs a `percpu_ref_put()` write into kfree\u0027d memory. Both are exploitable write/execute primitives after heap grooming.\\nA:H - The bug reproduces as an immediate kernel oops \\u2014 a general protection fault in `blkcg_set_ioprio()` from `submit_bio()` on a torn-down request queue, as recorded in the fix commit. A remote initiator can trigger this deterministically, panicking the storage target.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"74d16965d7ac378d28ebd833ae6d6a097186a4ec\", \"lessThan\": \"cc0607594f6813342b27c752c6fb6f6eb9980cb5\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"74d16965d7ac378d28ebd833ae6d6a097186a4ec\", \"lessThan\": \"4082326807072b71496501b6a0c55ffe8d5092a5\", \"versionType\": \"git\"}], \"programFiles\": [\"drivers/nvme/target/core.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"6.13\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"6.13\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"6.13.5\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.13.*\"}, {\"status\": \"unaffected\", \"version\": \"6.14\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"drivers/nvme/target/core.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/cc0607594f6813342b27c752c6fb6f6eb9980cb5\"}, {\"url\": \"https://git.kernel.org/stable/c/4082326807072b71496501b6a0c55ffe8d5092a5\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnvmet: Fix crash when a namespace is disabled\\n\\nThe namespace percpu counter protects pending I/O, and we can\\nonly safely diable the namespace once the counter drop to zero.\\nOtherwise we end up with a crash when running blktests/nvme/058\\n(eg for loop transport):\\n\\n[ 2352.930426] [  T53909] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI\\n[ 2352.930431] [  T53909] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]\\n[ 2352.930434] [  T53909] CPU: 3 UID: 0 PID: 53909 Comm: kworker/u16:5 Tainted: G        W          6.13.0-rc6 #232\\n[ 2352.930438] [  T53909] Tainted: [W]=WARN\\n[ 2352.930440] [  T53909] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014\\n[ 2352.930443] [  T53909] Workqueue: nvmet-wq nvme_loop_execute_work [nvme_loop]\\n[ 2352.930449] [  T53909] RIP: 0010:blkcg_set_ioprio+0x44/0x180\\n\\nas the queue is already torn down when calling submit_bio();\\n\\nSo we need to init the percpu counter in nvmet_ns_enable(), and\\nwait for it to drop to zero in nvmet_ns_disable() to avoid having\\nI/O pending after the namespace has been disabled.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.13.5\", \"versionStartIncluding\": \"6.13\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.14\", \"versionStartIncluding\": \"6.13\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T11:54:53.966Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2025-21850\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T11:54:53.966Z\", \"dateReserved\": \"2024-12-29T08:45:45.779Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2025-03-12T09:42:05.761Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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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.


Detection rules are retrieved from Rulezet.