Vulnerability-Lookup

FKIE_CVE-2021-4454

Vulnerability from fkie_nvd - Published: 2025-03-27 17:15 - Updated: 2026-10-15 22:17

Severity

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

Summary

In the Linux kernel, the following vulnerability has been resolved: can: j1939: fix errant WARN_ON_ONCE in j1939_session_deactivate The conclusion "j1939_session_deactivate() should be called with a session ref-count of at least 2" is incorrect. In some concurrent scenarios, j1939_session_deactivate can be called with the session ref-count less than 2. But there is not any problem because it will check the session active state before session putting in j1939_session_deactivate_locked(). Here is the concurrent scenario of the problem reported by syzbot and my reproduction log. cpu0 cpu1 j1939_xtp_rx_eoma j1939_xtp_rx_abort_one j1939_session_get_by_addr [kref == 2] j1939_session_get_by_addr [kref == 3] j1939_session_deactivate [kref == 2] j1939_session_put [kref == 1] j1939_session_completed j1939_session_deactivate WARN_ON_ONCE(kref < 2) ===================================================== WARNING: CPU: 1 PID: 21 at net/can/j1939/transport.c:1088 j1939_session_deactivate+0x5f/0x70 CPU: 1 PID: 21 Comm: ksoftirqd/1 Not tainted 5.14.0-rc7+ #32 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:j1939_session_deactivate+0x5f/0x70 Call Trace: j1939_session_deactivate_activate_next+0x11/0x28 j1939_xtp_rx_eoma+0x12a/0x180 j1939_tp_recv+0x4a2/0x510 j1939_can_recv+0x226/0x380 can_rcv_filter+0xf8/0x220 can_receive+0x102/0x220 ? process_backlog+0xf0/0x2c0 can_rcv+0x53/0xf0 __netif_receive_skb_one_core+0x67/0x90 ? process_backlog+0x97/0x2c0 __netif_receive_skb+0x22/0x80

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/1740a1e45eee65099a92fb502e1e67e63aad277d	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/6950df42a03c9ac9290503ced3f371199cb68fa9	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/9ab896775f98ff54b68512f345eed178bf961084	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b6d44072117bba057d50f7a2f96e5d070c65926d	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d0553680f94c49bbe0e39eb50d033ba563b4212d	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	5.14
linux	linux_kernel	5.14
linux	linux_kernel	5.14
linux	linux_kernel	5.14
linux	linux_kernel	5.14
linux	linux_kernel	6.2
linux	linux_kernel	6.2
linux	linux_kernel	6.2
linux	linux_kernel	6.2
linux	linux_kernel	6.2
linux	linux_kernel	6.2

JSON

To clipboard

{
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          "product": "Linux",
          "programFiles": [
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              "status": "unaffected",
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            },
            {
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            {
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            },
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: j1939: fix errant WARN_ON_ONCE in j1939_session_deactivate\n\nThe conclusion \"j1939_session_deactivate() should be called with a\nsession ref-count of at least 2\" is incorrect. In some concurrent\nscenarios, j1939_session_deactivate can be called with the session\nref-count less than 2. But there is not any problem because it\nwill check the session active state before session putting in\nj1939_session_deactivate_locked().\n\nHere is the concurrent scenario of the problem reported by syzbot\nand my reproduction log.\n\n        cpu0                            cpu1\n                                j1939_xtp_rx_eoma\nj1939_xtp_rx_abort_one\n                                j1939_session_get_by_addr [kref == 2]\nj1939_session_get_by_addr [kref == 3]\nj1939_session_deactivate [kref == 2]\nj1939_session_put [kref == 1]\n\t\t\t\tj1939_session_completed\n\t\t\t\tj1939_session_deactivate\n\t\t\t\tWARN_ON_ONCE(kref \u003c 2)\n\n=====================================================\nWARNING: CPU: 1 PID: 21 at net/can/j1939/transport.c:1088 j1939_session_deactivate+0x5f/0x70\nCPU: 1 PID: 21 Comm: ksoftirqd/1 Not tainted 5.14.0-rc7+ #32\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014\nRIP: 0010:j1939_session_deactivate+0x5f/0x70\nCall Trace:\n j1939_session_deactivate_activate_next+0x11/0x28\n j1939_xtp_rx_eoma+0x12a/0x180\n j1939_tp_recv+0x4a2/0x510\n j1939_can_recv+0x226/0x380\n can_rcv_filter+0xf8/0x220\n can_receive+0x102/0x220\n ? process_backlog+0xf0/0x2c0\n can_rcv+0x53/0xf0\n __netif_receive_skb_one_core+0x67/0x90\n ? process_backlog+0x97/0x2c0\n __netif_receive_skb+0x22/0x80"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: can: j1939: correcci\u00f3n del error WARN_ON_ONCE en j1939_session_deactivate. La conclusi\u00f3n \"j1939_session_deactivate() debe llamarse con un recuento de referencias de sesi\u00f3n de al menos 2\" es incorrecta. En algunos escenarios concurrentes, se puede llamar a j1939_session_deactivate con un recuento de referencias de sesi\u00f3n inferior a 2. Sin embargo, no hay problema, ya que comprueba el estado activo de la sesi\u00f3n antes de que se active j1939_session_deactivate_locked(). A continuaci\u00f3n, se muestra el escenario concurrente del problema reportado por syzbot y mi registro de reproducci\u00f3n. cpu0 cpu1 j1939_xtp_rx_eoma j1939_xtp_rx_abort_one j1939_session_get_by_addr [kref == 2] j1939_session_get_by_addr [kref == 3] j1939_session_deactivate [kref == 2] j1939_session_put [kref == 1] j1939_session_completed j1939_session_deactivate WARN_ON_ONCE(kref \u0026lt; 2)  ======================================================= ADVERTENCIA: CPU: 1 PID: 21 at net/can/j1939/transport.c:1088 j1939_session_deactivate+0x5f/0x70 CPU: 1 PID: 21 Comm: ksoftirqd/1 Not tainted 5.14.0-rc7+ #32 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:j1939_session_deactivate+0x5f/0x70 Call Trace: j1939_session_deactivate_activate_next+0x11/0x28 j1939_xtp_rx_eoma+0x12a/0x180 j1939_tp_recv+0x4a2/0x510 j1939_can_recv+0x226/0x380 can_rcv_filter+0xf8/0x220 can_receive+0x102/0x220 ? process_backlog+0xf0/0x2c0 can_rcv+0x53/0xf0 __netif_receive_skb_one_core+0x67/0x90 ? process_backlog+0x97/0x2c0 __netif_receive_skb+0x22/0x80 "
    }
  ],
  "id": "CVE-2021-4454",
  "lastModified": "2026-10-15T22:17:22.303",
  "metrics": {
    "cvssMetricV31": [
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        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
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          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
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          "userInteraction": "NONE",
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        "source": "nvd@nist.gov",
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          "role": "CISA Coordinator",
          "timestamp": "2026-10-15T21:02:43.206452Z",
          "version": "2.0.3"
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  "published": "2025-03-27T17:15:35.820",
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
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        {
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}

CVE-2021-4454 (GCVE-0-2021-4454)

Vulnerability from cvelistv5 – Published: 2025-03-27 16:37 – Updated: 2026-10-15 21:21

Title

can: j1939: fix errant WARN_ON_ONCE in j1939_session_deactivate

Summary

Severity

7.5 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-15 21:02 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6820 records in the last 180 days details

References

5 references

URL	Tags
https://git.kernel.org/stable/c/6950df42a03c9ac92…
https://git.kernel.org/stable/c/b6d44072117bba057…
https://git.kernel.org/stable/c/9ab896775f98ff54b…
https://git.kernel.org/stable/c/1740a1e45eee65099…
https://git.kernel.org/stable/c/d0553680f94c49bbe…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 7eef18c0479ba5d9f54fba30cd77c233ebca3eb1 , < 6950df42a03c9ac9290503ced3f371199cb68fa9 (git) Affected: 55dd22c5d029423f513fd849e633adf0e9c10d0c , < b6d44072117bba057d50f7a2f96e5d070c65926d (git) Affected: 0c71437dd50dd687c15d8ca80b3b68f10bb21d63 , < 9ab896775f98ff54b68512f345eed178bf961084 (git) Affected: 0c71437dd50dd687c15d8ca80b3b68f10bb21d63 , < 1740a1e45eee65099a92fb502e1e67e63aad277d (git) Affected: 0c71437dd50dd687c15d8ca80b3b68f10bb21d63 , < d0553680f94c49bbe0e39eb50d033ba563b4212d (git) Affected: 5e1fc537c1be332aef9621ca9146aeb3ba59522f (git) Affected: 5.4.138 , < 5.4.232 (semver) Affected: 5.10.56 , < 5.10.168 (semver) Affected: 5.13.8 , < 5.14 (semver)
Linux	Linux	Affected: 5.14 Unaffected: 0 , < 5.14 (semver) Unaffected: 5.4.232 , ≤ 5.4.* (semver) Unaffected: 5.10.168 , ≤ 5.10.* (semver) Unaffected: 5.15.93 , ≤ 5.15.* (semver) Unaffected: 6.1.11 , ≤ 6.1.* (semver) Unaffected: 6.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-4454",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-15T21:02:43.206452Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-15T21:21:06.266Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/can/j1939/transport.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6950df42a03c9ac9290503ced3f371199cb68fa9",
              "status": "affected",
              "version": "7eef18c0479ba5d9f54fba30cd77c233ebca3eb1",
              "versionType": "git"
            },
            {
              "lessThan": "b6d44072117bba057d50f7a2f96e5d070c65926d",
              "status": "affected",
              "version": "55dd22c5d029423f513fd849e633adf0e9c10d0c",
              "versionType": "git"
            },
            {
              "lessThan": "9ab896775f98ff54b68512f345eed178bf961084",
              "status": "affected",
              "version": "0c71437dd50dd687c15d8ca80b3b68f10bb21d63",
              "versionType": "git"
            },
            {
              "lessThan": "1740a1e45eee65099a92fb502e1e67e63aad277d",
              "status": "affected",
              "version": "0c71437dd50dd687c15d8ca80b3b68f10bb21d63",
              "versionType": "git"
            },
            {
              "lessThan": "d0553680f94c49bbe0e39eb50d033ba563b4212d",
              "status": "affected",
              "version": "0c71437dd50dd687c15d8ca80b3b68f10bb21d63",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5e1fc537c1be332aef9621ca9146aeb3ba59522f",
              "versionType": "git"
            },
            {
              "lessThan": "5.4.232",
              "status": "affected",
              "version": "5.4.138",
              "versionType": "semver"
            },
            {
              "lessThan": "5.10.168",
              "status": "affected",
              "version": "5.10.56",
              "versionType": "semver"
            },
            {
              "lessThan": "5.14",
              "status": "affected",
              "version": "5.13.8",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/can/j1939/transport.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.14"
            },
            {
              "lessThan": "5.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.232",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.168",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.93",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.232",
                  "versionStartIncluding": "5.4.138",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.168",
                  "versionStartIncluding": "5.10.56",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.93",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.11",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.2",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.13.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: j1939: fix errant WARN_ON_ONCE in j1939_session_deactivate\n\nThe conclusion \"j1939_session_deactivate() should be called with a\nsession ref-count of at least 2\" is incorrect. In some concurrent\nscenarios, j1939_session_deactivate can be called with the session\nref-count less than 2. But there is not any problem because it\nwill check the session active state before session putting in\nj1939_session_deactivate_locked().\n\nHere is the concurrent scenario of the problem reported by syzbot\nand my reproduction log.\n\n        cpu0                            cpu1\n                                j1939_xtp_rx_eoma\nj1939_xtp_rx_abort_one\n                                j1939_session_get_by_addr [kref == 2]\nj1939_session_get_by_addr [kref == 3]\nj1939_session_deactivate [kref == 2]\nj1939_session_put [kref == 1]\n\t\t\t\tj1939_session_completed\n\t\t\t\tj1939_session_deactivate\n\t\t\t\tWARN_ON_ONCE(kref \u003c 2)\n\n=====================================================\nWARNING: CPU: 1 PID: 21 at net/can/j1939/transport.c:1088 j1939_session_deactivate+0x5f/0x70\nCPU: 1 PID: 21 Comm: ksoftirqd/1 Not tainted 5.14.0-rc7+ #32\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014\nRIP: 0010:j1939_session_deactivate+0x5f/0x70\nCall Trace:\n j1939_session_deactivate_activate_next+0x11/0x28\n j1939_xtp_rx_eoma+0x12a/0x180\n j1939_tp_recv+0x4a2/0x510\n j1939_can_recv+0x226/0x380\n can_rcv_filter+0xf8/0x220\n can_receive+0x102/0x220\n ? process_backlog+0xf0/0x2c0\n can_rcv+0x53/0xf0\n __netif_receive_skb_one_core+0x67/0x90\n ? process_backlog+0x97/0x2c0\n __netif_receive_skb+0x22/0x80"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The WARN fires on the packet receive path (can_rcv \u2192 j1939_can_recv \u2192 j1939_tp_recv \u2192 j1939_xtp_rx_eoma/abort \u2192 j1939_session_deactivate). An unauthenticated CAN/J1939 peer can trigger it without local code on the target, consistent with other packet-triggered j1939 scores (e.g. CVE-2023-52887, CVE-2026-22997).\nAC:L - The attacker controls both sides of the race by injecting concurrent TP.CM EOMA and Abort frames for the same session; packet content and timing are fully attacker-influenced, so success does not depend on external conditions.\nPR:N - J1939/CAN receive processing has no authentication or credential check; once a legitimate J1939 socket is bound (normal deployment state), an unauthenticated bus peer can inject the crafted frame sequence.\nUI:N - Frames are processed automatically in softirq receive context; no victim or administrator action is required beyond the target already running the J1939 stack.\nS:U - Impact is confined to kernel J1939 session handling within the same host kernel authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:N - The defect is only a spurious WARN_ON_ONCE; the concurrent deactivate path checks session active state before putting, and investigation found no info leak, OOB read, or UAF disclosure primitive.\nI:N - No out-of-bounds write, type confusion, or other integrity/write primitive exists\u2014the fix only removes an incorrect assertion while leaving correct deactivate_locked behavior unchanged.\nA:H - WARN_ON_ONCE in softirq receive context can panic the kernel when panic_on_warn is set (and warn_limit exhaustion similarly), producing a denial of service inducible by an unauthenticated peer."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:44:58.812Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6950df42a03c9ac9290503ced3f371199cb68fa9"
        },
        {
          "url": "https://git.kernel.org/stable/c/b6d44072117bba057d50f7a2f96e5d070c65926d"
        },
        {
          "url": "https://git.kernel.org/stable/c/9ab896775f98ff54b68512f345eed178bf961084"
        },
        {
          "url": "https://git.kernel.org/stable/c/1740a1e45eee65099a92fb502e1e67e63aad277d"
        },
        {
          "url": "https://git.kernel.org/stable/c/d0553680f94c49bbe0e39eb50d033ba563b4212d"
        }
      ],
      "title": "can: j1939: fix errant WARN_ON_ONCE in j1939_session_deactivate",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-4454",
    "datePublished": "2025-03-27T16:37:09.381Z",
    "dateReserved": "2025-02-26T02:29:43.631Z",
    "dateUpdated": "2026-10-15T21:21:06.266Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

Vulnerability timeline

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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.
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