CVE-2026-31772 (GCVE-0-2026-31772)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-05-23 16:05
VLAI
Title
Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync hci_le_big_create_sync() uses DEFINE_FLEX to allocate a struct hci_cp_le_big_create_sync on the stack with room for 0x11 (17) BIS entries. However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31) entries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller hci_conn_big_create_sync(). When conn->num_bis is between 18 and 31, the memcpy that copies conn->bis into cp->bis writes up to 14 bytes past the stack buffer, corrupting adjacent stack memory. This is trivially reproducible: binding an ISO socket with bc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will eventually trigger hci_le_big_create_sync() from the HCI command sync worker, causing a KASAN-detectable stack-out-of-bounds write: BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0 Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71 Fix this by changing the DEFINE_FLEX count from the incorrect 0x11 to HCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that conn->bis can actually carry.
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
Linux Linux Affected: 91d19383b7ed035e22165ae5c836e50bb9f95fbe , < f5d446624345d309e7a4a1b27ea9f028d6a8c5d9 (git)
Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < aba0aea354015794e8312dd7efe726967e58aefe (git)
Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < eaf32002ca7b1ba51c9f140991fd9febe6de79f0 (git)
Affected: 42ecf1947135110ea08abeaca39741636f9a2285 , < bc39a094730ce062fa034a529c93147c096cb488 (git)
Affected: 8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd (git)
Affected: 6.12.2 , < 6.12.81 (semver)
Affected: 6.11.11 , < 6.12 (semver)
Create a notification for this product.
Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (semver)
Unaffected: 6.12.81 , ≤ 6.12.* (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f5d446624345d309e7a4a1b27ea9f028d6a8c5d9",
              "status": "affected",
              "version": "91d19383b7ed035e22165ae5c836e50bb9f95fbe",
              "versionType": "git"
            },
            {
              "lessThan": "aba0aea354015794e8312dd7efe726967e58aefe",
              "status": "affected",
              "version": "42ecf1947135110ea08abeaca39741636f9a2285",
              "versionType": "git"
            },
            {
              "lessThan": "eaf32002ca7b1ba51c9f140991fd9febe6de79f0",
              "status": "affected",
              "version": "42ecf1947135110ea08abeaca39741636f9a2285",
              "versionType": "git"
            },
            {
              "lessThan": "bc39a094730ce062fa034a529c93147c096cb488",
              "status": "affected",
              "version": "42ecf1947135110ea08abeaca39741636f9a2285",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd",
              "versionType": "git"
            },
            {
              "lessThan": "6.12.81",
              "status": "affected",
              "version": "6.12.2",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12",
              "status": "affected",
              "version": "6.11.11",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.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": "6.12.*",
              "status": "unaffected",
              "version": "6.12.81",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.22",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.81",
                  "versionStartIncluding": "6.12.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.22",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.12",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.11.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync\n\nhci_le_big_create_sync() uses DEFINE_FLEX to allocate a\nstruct hci_cp_le_big_create_sync on the stack with room for 0x11 (17)\nBIS entries.  However, conn-\u003enum_bis can hold up to HCI_MAX_ISO_BIS (31)\nentries \u2014 validated against ISO_MAX_NUM_BIS (0x1f) in the caller\nhci_conn_big_create_sync().  When conn-\u003enum_bis is between 18 and 31,\nthe memcpy that copies conn-\u003ebis into cp-\u003ebis writes up to 14 bytes\npast the stack buffer, corrupting adjacent stack memory.\n\nThis is trivially reproducible: binding an ISO socket with\nbc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will\neventually trigger hci_le_big_create_sync() from the HCI command\nsync worker, causing a KASAN-detectable stack-out-of-bounds write:\n\n  BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0\n  Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71\n\nFix this by changing the DEFINE_FLEX count from the incorrect 0x11 to\nHCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that\nconn-\u003ebis can actually carry."
        }
      ],
      "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"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-23T16:05:54.091Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9"
        },
        {
          "url": "https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe"
        },
        {
          "url": "https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0"
        },
        {
          "url": "https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488"
        }
      ],
      "title": "Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31772",
    "datePublished": "2026-05-01T14:15:00.582Z",
    "dateReserved": "2026-03-09T15:48:24.140Z",
    "dateUpdated": "2026-05-23T16:05:54.091Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-31772",
      "date": "2026-06-30",
      "epss": "0.00142",
      "percentile": "0.03877"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-31772\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-01T15:16:40.470\",\"lastModified\":\"2026-06-17T10:34:26.100\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nBluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync\\n\\nhci_le_big_create_sync() uses DEFINE_FLEX to allocate a\\nstruct hci_cp_le_big_create_sync on the stack with room for 0x11 (17)\\nBIS entries.  However, conn-\u003enum_bis can hold up to HCI_MAX_ISO_BIS (31)\\nentries \u2014 validated against ISO_MAX_NUM_BIS (0x1f) in the caller\\nhci_conn_big_create_sync().  When conn-\u003enum_bis is between 18 and 31,\\nthe memcpy that copies conn-\u003ebis into cp-\u003ebis writes up to 14 bytes\\npast the stack buffer, corrupting adjacent stack memory.\\n\\nThis is trivially reproducible: binding an ISO socket with\\nbc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will\\neventually trigger hci_le_big_create_sync() from the HCI command\\nsync worker, causing a KASAN-detectable stack-out-of-bounds write:\\n\\n  BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0\\n  Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71\\n\\nFix this by changing the DEFINE_FLEX count from the incorrect 0x11 to\\nHCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that\\nconn-\u003ebis can actually carry.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/bluetooth/hci_sync.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"91d19383b7ed035e22165ae5c836e50bb9f95fbe\",\"lessThan\":\"f5d446624345d309e7a4a1b27ea9f028d6a8c5d9\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"42ecf1947135110ea08abeaca39741636f9a2285\",\"lessThan\":\"aba0aea354015794e8312dd7efe726967e58aefe\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"42ecf1947135110ea08abeaca39741636f9a2285\",\"lessThan\":\"eaf32002ca7b1ba51c9f140991fd9febe6de79f0\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"42ecf1947135110ea08abeaca39741636f9a2285\",\"lessThan\":\"bc39a094730ce062fa034a529c93147c096cb488\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"6.12.2\",\"lessThan\":\"6.12.81\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.11.11\",\"lessThan\":\"6.12\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/bluetooth/hci_sync.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.13\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.13\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.81\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.22\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.19.12\",\"lessThanOrEqual\":\"6.19.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0\",\"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}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-787\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.11.11\",\"versionEndExcluding\":\"6.12\",\"matchCriteriaId\":\"4CBF5F6E-D446-4CAE-AAA4-413442319824\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.12.2\",\"versionEndExcluding\":\"6.12.81\",\"matchCriteriaId\":\"2B5546BA-4E7F-4FB9-9ED6-3DD23FE96C38\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.13.1\",\"versionEndExcluding\":\"6.18.22\",\"matchCriteriaId\":\"8CBC12FA-A2A3-4882-BEB3-38ED3AC5AD57\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.19\",\"versionEndExcluding\":\"6.19.12\",\"matchCriteriaId\":\"0A2B9540-02D5-41B4-B16A-82AF66FD4F36\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.13:-:*:*:*:*:*:*\",\"matchCriteriaId\":\"5A3F9505-6B98-4269-8B81-127E55A1BF00\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"F253B622-8837-4245-BCE5-A7BF8FC76A16\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"F666C8D8-6538-46D4-B318-87610DE64C34\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*\",\"matchCriteriaId\":\"02259FDA-961B-47BC-AE7F-93D7EC6E90C2\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*\",\"matchCriteriaId\":\"58A9FEFF-C040-420D-8F0A-BFDAAA1DF258\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*\",\"matchCriteriaId\":\"1D2315C0-D46F-4F85-9754-F9E5E11374A6\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.