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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 · CISA-ADP (v2.0.3)
Decision recorded 2025-10-01 19:26 UTC
CWE
  • CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
Assigner
References
Impacted products
Vendor Product Version CPE status
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)
guessed Create a notification for this product.
Show details on NVD website
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            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nvmet: corrige el fallo cuando se deshabilita un espacio de nombres. 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 tener E/S pendiente despu\u00e9s de que se haya deshabilitado el espacio de nombres."
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                  "baseSeverity": "MEDIUM",
                  "confidentialityImpact": "NONE",
                  "integrityImpact": "NONE",
                  "privilegesRequired": "LOW",
                  "scope": "UNCHANGED",
                  "userInteraction": "NONE",
                  "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                  "version": "3.1"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2025-21850",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2025-10-01T19:26:16.776927Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-835",
                    "description": "CWE-835 Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027)",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2025-10-01T16:58:15.211Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "drivers/nvme/target/core.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "cc0607594f6813342b27c752c6fb6f6eb9980cb5",
                  "status": "affected",
                  "version": "74d16965d7ac378d28ebd833ae6d6a097186a4ec",
                  "versionType": "git"
                },
                {
                  "lessThan": "4082326807072b71496501b6a0c55ffe8d5092a5",
                  "status": "affected",
                  "version": "74d16965d7ac378d28ebd833ae6d6a097186a4ec",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "drivers/nvme/target/core.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "6.13"
                },
                {
                  "lessThan": "6.13",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.13.*",
                  "status": "unaffected",
                  "version": "6.13.5",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "6.14",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.13.5",
                      "versionStartIncluding": "6.13",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.14",
                      "versionStartIncluding": "6.13",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "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."
            }
          ],
          "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 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."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-05T11:54:53.966Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/cc0607594f6813342b27c752c6fb6f6eb9980cb5"
            },
            {
              "url": "https://git.kernel.org/stable/c/4082326807072b71496501b6a0c55ffe8d5092a5"
            }
          ],
          "title": "nvmet: Fix crash when a namespace is disabled",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2025-21850",
        "datePublished": "2025-03-12T09:42:05.761Z",
        "dateReserved": "2024-12-29T08:45:45.779Z",
        "dateUpdated": "2026-08-05T11:54:53.966Z",
        "state": "PUBLISHED"
      },
      "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.


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.