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CVE-2026-89763 (GCVE-0-2026-89763)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:47 – Updated: 2026-09-13 06:34
VLAI
Title
KEYS: trusted: Fix TPM teardown ordering
Summary
In the Linux kernel, the following vulnerability has been resolved: KEYS: trusted: Fix TPM teardown ordering trusted_tpm_exit() drops the TPM chip reference and frees the digest array before unregistering the trusted key type. key_type_lookup() holds key_types_sem for reading until the key operation finishes, while unregister_key_type() takes it for writing. It therefore provides the synchronization point that must precede backend teardown. The current order permits this interleaving: CPU 0 CPU 1 trusted_tpm_exit() key_type_lookup("trusted") put_device(&chip->dev) trusted_tpm_seal() kfree(digests) pcrlock() unregister_key_type() tpm_pcr_extend(..., digests) CPU 1 can consequently dereference the freed digest array. The chip can also be released before callbacks stop using it. KASAN reported: BUG: KASAN: slab-use-after-free in tpm_pcr_extend+0x1f0/0x200 Read of size 2 at addr ffff88810872d000 by task poc/89 Call Trace: tpm_pcr_extend+0x1f0/0x200 pcrlock+0x42/0x70 [trusted] trusted_tpm_seal+0x1b6/0x570 [trusted] trusted_instantiate+0x293/0x340 [trusted] __key_instantiate_and_link+0xb2/0x2b0 __key_create_or_update+0x61e/0xb50 __do_sys_add_key+0x1b8/0x310 Allocated by task 88: __kmalloc_noprof+0x1a7/0x490 do_one_initcall+0xa1/0x390 do_init_module+0x2df/0x840 Freed by task 90: kfree+0x131/0x3c0 trusted_tpm_exit+0x59/0xa0 [trusted] __do_sys_delete_module+0x346/0x510 Move unregister_key_type() before releasing either resource. This stops new lookups and waits for in-flight key operations to finish before the backend state is destroyed.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 , < 753c978f2400f9783eb524842a975d3ac950d511 (git)
Affected: 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 , < 2f7541afbc57fe9d26769a22c31d8ce8790c9a19 (git)
Affected: 0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400 , < 5e2d672280d97d83de43031d93761b12dadd7b8a (git)
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Linux Linux Affected: 5.1
Unaffected: 0 , < 5.1 (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "security/keys/trusted-keys/trusted_tpm1.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "status": "affected",
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              "versionType": "git"
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        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.1"
            },
            {
              "lessThan": "5.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "5.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "5.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "5.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKEYS: trusted: Fix TPM teardown ordering\n\ntrusted_tpm_exit() drops the TPM chip reference and frees the digest\narray before unregistering the trusted key type. key_type_lookup()\nholds key_types_sem for reading until the key operation finishes, while\nunregister_key_type() takes it for writing. It therefore provides the\nsynchronization point that must precede backend teardown.\n\nThe current order permits this interleaving:\n\n  CPU 0                              CPU 1\n  trusted_tpm_exit()                 key_type_lookup(\"trusted\")\n    put_device(\u0026chip-\u003edev)             trusted_tpm_seal()\n    kfree(digests)                       pcrlock()\n    unregister_key_type()                  tpm_pcr_extend(..., digests)\n\nCPU 1 can consequently dereference the freed digest array. The chip can\nalso be released before callbacks stop using it.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in tpm_pcr_extend+0x1f0/0x200\n  Read of size 2 at addr ffff88810872d000 by task poc/89\n  Call Trace:\n    tpm_pcr_extend+0x1f0/0x200\n    pcrlock+0x42/0x70 [trusted]\n    trusted_tpm_seal+0x1b6/0x570 [trusted]\n    trusted_instantiate+0x293/0x340 [trusted]\n    __key_instantiate_and_link+0xb2/0x2b0\n    __key_create_or_update+0x61e/0xb50\n    __do_sys_add_key+0x1b8/0x310\n  Allocated by task 88:\n    __kmalloc_noprof+0x1a7/0x490\n    do_one_initcall+0xa1/0x390\n    do_init_module+0x2df/0x840\n  Freed by task 90:\n    kfree+0x131/0x3c0\n    trusted_tpm_exit+0x59/0xa0 [trusted]\n    __do_sys_delete_module+0x346/0x510\n\nMove unregister_key_type() before releasing either resource. This stops\nnew lookups and waits for in-flight key operations to finish before the\nbackend state is destroyed."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached only via the local add_key(2) syscall (trusted_instantiate \u2192 trusted_tpm_seal \u2192 pcrlock/tpm_* on global chip/digests) racing trusted_tpm_exit() during delete_module of trusted.ko; no network or adjacent protocol processes this key-type teardown.\nAC:L - The attacker controls both sides of the race by issuing concurrent add_key(\"trusted\") while trusted.ko is unloaded; key_type_lookup() still succeeds until unregister_key_type(), so the documented CPU0/CPU1 interleaving is reliably repeatable without uncontrollable victim memory layout.\nPR:L - add_key(2) on a caller-owned keyring has no capable() check in trusted_instantiate(); every seal/unseal uses the global chip after put_device, and only optional pcrlock() needs CAP_SYS_ADMIN. Per CNA driver-removal UAF precedent, concurrent rmmod of trusted.ko does not require the attacker to hold CAP_SYS_MODULE.\nUI:N - Exploitation is driven by the attacker\u0027s own add_key threads and module-unload timing; no separate victim must mount a filesystem, open a device, or take any other action.\nS:U - The vulnerability is a standard in-kernel slab use-after-free affecting host kernel memory and availability; it does not cross a VM, IOMMU, or other distinct security-authority boundary.\nC:H - KASAN shows a slab-use-after-free read of the freed digests array in tpm_pcr_extend, and put_device may free tpm_chip while callbacks still dereference it; per kernel CNA guidance a UAF enables object reuse and arbitrary kernel read, so Confidentiality is High.\nI:H - Seal/unseal after teardown calls tpm_try_get_ops() which mutates chip (get_device, mutex_lock) and PCR extend consumes the UAF\u0027d digest buffer; use-after-free is heap-sprayable into write and control-flow primitives, so Integrity is High.\nA:H - The KASAN report is a kernel slab-use-after-free oops during add_key versus delete_module; any such UAF can panic or hang the kernel, scoring Availability High even when not fully exploited for code execution."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:34:07.588Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/753c978f2400f9783eb524842a975d3ac950d511"
        },
        {
          "url": "https://git.kernel.org/stable/c/2f7541afbc57fe9d26769a22c31d8ce8790c9a19"
        },
        {
          "url": "https://git.kernel.org/stable/c/5e2d672280d97d83de43031d93761b12dadd7b8a"
        }
      ],
      "title": "KEYS: trusted: Fix TPM teardown ordering",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89763",
    "datePublished": "2026-09-11T19:47:04.352Z",
    "dateReserved": "2026-09-11T19:38:34.764Z",
    "dateUpdated": "2026-09-13T06:34:07.588Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-89763",
      "date": "2026-09-16",
      "epss": "0.00115",
      "percentile": "0.01762"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-89763\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-11T20:20:07.523\",\"lastModified\":\"2026-09-13T07:17:40.717\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nKEYS: trusted: Fix TPM teardown ordering\\n\\ntrusted_tpm_exit() drops the TPM chip reference and frees the digest\\narray before unregistering the trusted key type. key_type_lookup()\\nholds key_types_sem for reading until the key operation finishes, while\\nunregister_key_type() takes it for writing. It therefore provides the\\nsynchronization point that must precede backend teardown.\\n\\nThe current order permits this interleaving:\\n\\n  CPU 0                              CPU 1\\n  trusted_tpm_exit()                 key_type_lookup(\\\"trusted\\\")\\n    put_device(\u0026chip-\u003edev)             trusted_tpm_seal()\\n    kfree(digests)                       pcrlock()\\n    unregister_key_type()                  tpm_pcr_extend(..., digests)\\n\\nCPU 1 can consequently dereference the freed digest array. The chip can\\nalso be released before callbacks stop using it.\\n\\nKASAN reported:\\n\\n  BUG: KASAN: slab-use-after-free in tpm_pcr_extend+0x1f0/0x200\\n  Read of size 2 at addr ffff88810872d000 by task poc/89\\n  Call Trace:\\n    tpm_pcr_extend+0x1f0/0x200\\n    pcrlock+0x42/0x70 [trusted]\\n    trusted_tpm_seal+0x1b6/0x570 [trusted]\\n    trusted_instantiate+0x293/0x340 [trusted]\\n    __key_instantiate_and_link+0xb2/0x2b0\\n    __key_create_or_update+0x61e/0xb50\\n    __do_sys_add_key+0x1b8/0x310\\n  Allocated by task 88:\\n    __kmalloc_noprof+0x1a7/0x490\\n    do_one_initcall+0xa1/0x390\\n    do_init_module+0x2df/0x840\\n  Freed by task 90:\\n    kfree+0x131/0x3c0\\n    trusted_tpm_exit+0x59/0xa0 [trusted]\\n    __do_sys_delete_module+0x346/0x510\\n\\nMove unregister_key_type() before releasing either resource. This stops\\nnew lookups and waits for in-flight key operations to finish before the\\nbackend state is destroyed.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"security/keys/trusted-keys/trusted_tpm1.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400\",\"lessThan\":\"753c978f2400f9783eb524842a975d3ac950d511\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400\",\"lessThan\":\"2f7541afbc57fe9d26769a22c31d8ce8790c9a19\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0b6cf6b97b7ef1fa3c7fefab0cac897a1c4a3400\",\"lessThan\":\"5e2d672280d97d83de43031d93761b12dadd7b8a\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"security/keys/trusted-keys/trusted_tpm1.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.50\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2f7541afbc57fe9d26769a22c31d8ce8790c9a19\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5e2d672280d97d83de43031d93761b12dadd7b8a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/753c978f2400f9783eb524842a975d3ac950d511\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-13T06:52:58+00:00",
      "cve": "CVE-2026-89763",
      "id": "CVE-2026-89763",
      "initial_release_date": "2026-09-11T19:47:04.352000+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: Use-after-free in TPM trusted keys due to incorrect teardown ordering",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89763.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-12T16:22:00Z",
      "cve": "CVE-2026-89763",
      "id": "CVE-2026-89763",
      "initial_release_date": "2026-09-12T16:22:00Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89763",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89763.json",
      "version": "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.

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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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