CVE-2026-64048 (GCVE-0-2026-64048)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:39 – Updated: 2026-07-20 13:42
VLAI
Title
net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot
Summary
In the Linux kernel, the following vulnerability has been resolved: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot On the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is reserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt() populates V2 entries starting at index 1, so when no V1 device is selected slot 0 is left in its kzalloc()'ed state with ism_dev[0] == NULL and ism_chid[0] == 0. smc_v2_determine_accepted_chid() then matches the peer's CHID against the array starting from index 0 using the CHID alone. A malicious peer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches the empty slot, ini->ism_selected becomes 0, and the subsequent ism_dev[0]->lgr_lock dereference in smc_conn_create() faults at offsetof(struct smcd_dev, lgr_lock) == 0x68: BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0 Write of size 4 at addr 0000000000000068 by task exploit/144 Call Trace: _raw_spin_lock_bh smc_conn_create (net/smc/smc_core.c:1997) __smc_connect (net/smc/af_smc.c:1447) smc_connect (net/smc/af_smc.c:1720) __sys_connect __x64_sys_connect do_syscall_64 Require ism_dev[i] to be non-NULL before accepting a CHID match.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: a7c9c5f4af7f6098da68705fc5d86565d0728ef7 , < 6927cacf2b10d4fa80c1a2d407512ef9397c59c6 (git)
Affected: a7c9c5f4af7f6098da68705fc5d86565d0728ef7 , < d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0 (git)
Affected: a7c9c5f4af7f6098da68705fc5d86565d0728ef7 , < 53eb7bd09aace72fa17510d80e0caf5ca058c231 (git)
Affected: a7c9c5f4af7f6098da68705fc5d86565d0728ef7 , < afa9036b8c9963947b487c36e332df6a42c96fcb (git)
Affected: a7c9c5f4af7f6098da68705fc5d86565d0728ef7 , < 65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e (git)
Affected: a7c9c5f4af7f6098da68705fc5d86565d0728ef7 , < 277740023def559a4a2ddc3e8e784ee37a0f16a9 (git)
Create a notification for this product.
Linux Linux Affected: 5.10
Unaffected: 0 , < 5.10 (semver)
Unaffected: 6.1.175 , ≤ 6.1.* (semver)
Unaffected: 6.6.142 , ≤ 6.6.* (semver)
Unaffected: 6.12.92 , ≤ 6.12.* (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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{
  "containers": {
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              "versionType": "original_commit_for_fix"
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              "cpeMatch": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot\n\nOn the SMC-D client, slot 0 of ini-\u003eism_dev[]/ini-\u003eism_chid[] is\nreserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt()\npopulates V2 entries starting at index 1, so when no V1 device is\nselected slot 0 is left in its kzalloc()\u0027ed state with ism_dev[0] ==\nNULL and ism_chid[0] == 0.\n\nsmc_v2_determine_accepted_chid() then matches the peer\u0027s CHID against\nthe array starting from index 0 using the CHID alone. A malicious\npeer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches\nthe empty slot, ini-\u003eism_selected becomes 0, and the subsequent\nism_dev[0]-\u003elgr_lock dereference in smc_conn_create() faults at\noffsetof(struct smcd_dev, lgr_lock) == 0x68:\n\n  BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0\n  Write of size 4 at addr 0000000000000068 by task exploit/144\n  Call Trace:\n   _raw_spin_lock_bh\n   smc_conn_create (net/smc/smc_core.c:1997)\n   __smc_connect (net/smc/af_smc.c:1447)\n   smc_connect (net/smc/af_smc.c:1720)\n   __sys_connect\n   __x64_sys_connect\n   do_syscall_64\n\nRequire ism_dev[i] to be non-NULL before accepting a CHID match."
        }
      ],
      "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"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T13:42:48.799Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0"
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        {
          "url": "https://git.kernel.org/stable/c/277740023def559a4a2ddc3e8e784ee37a0f16a9"
        }
      ],
      "title": "net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64048",
    "datePublished": "2026-07-19T15:39:32.664Z",
    "dateReserved": "2026-07-19T07:54:57.029Z",
    "dateUpdated": "2026-07-20T13:42:48.799Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-07-21",
      "epss": "0.00485",
      "percentile": "0.38682"
    },
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A malicious\\npeer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches\\nthe empty slot, ini-\u003eism_selected becomes 0, and the subsequent\\nism_dev[0]-\u003elgr_lock dereference in smc_conn_create() faults at\\noffsetof(struct smcd_dev, lgr_lock) == 0x68:\\n\\n  BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0\\n  Write of size 4 at addr 0000000000000068 by task exploit/144\\n  Call Trace:\\n   _raw_spin_lock_bh\\n   smc_conn_create (net/smc/smc_core.c:1997)\\n   __smc_connect (net/smc/af_smc.c:1447)\\n   smc_connect (net/smc/af_smc.c:1720)\\n   __sys_connect\\n   __x64_sys_connect\\n   do_syscall_64\\n\\nRequire ism_dev[i] to be non-NULL before accepting a CHID match.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/smc/af_smc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"a7c9c5f4af7f6098da68705fc5d86565d0728ef7\",\"lessThan\":\"6927cacf2b10d4fa80c1a2d407512ef9397c59c6\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a7c9c5f4af7f6098da68705fc5d86565d0728ef7\",\"lessThan\":\"d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a7c9c5f4af7f6098da68705fc5d86565d0728ef7\",\"lessThan\":\"53eb7bd09aace72fa17510d80e0caf5ca058c231\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a7c9c5f4af7f6098da68705fc5d86565d0728ef7\",\"lessThan\":\"afa9036b8c9963947b487c36e332df6a42c96fcb\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a7c9c5f4af7f6098da68705fc5d86565d0728ef7\",\"lessThan\":\"65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a7c9c5f4af7f6098da68705fc5d86565d0728ef7\",\"lessThan\":\"277740023def559a4a2ddc3e8e784ee37a0f16a9\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/smc/af_smc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.10\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.10\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.175\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.142\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.92\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.34\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.11\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/277740023def559a4a2ddc3e8e784ee37a0f16a9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/53eb7bd09aace72fa17510d80e0caf5ca058c231\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6927cacf2b10d4fa80c1a2d407512ef9397c59c6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/afa9036b8c9963947b487c36e332df6a42c96fcb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-20T17:08:26+00:00",
      "cve": "CVE-2026-64048",
      "id": "CVE-2026-64048",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "43",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64048.json",
      "version": "3"
    }
  }
}



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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

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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.


Detection rules are retrieved from Rulezet.