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Bluetooth: L2CAP: validate option length before reading conf opt value

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: validate option length before reading conf opt value l2cap_get_conf_opt() derives the option length from the attacker-controlled opt->len field and immediately dereferences opt->val (as u8, get_unaligned_le16() or get_unaligned_le32(), or a raw pointer for the default case) before any caller has confirmed that opt->len bytes are present in the buffer. The callers (l2cap_parse_conf_req(), l2cap_parse_conf_rsp() and l2cap_conf_rfc_get()) only detect a malformed option afterwards, once the running length has gone negative, by which point the out-of-bounds read has already executed. An existing post-hoc length check keeps the garbage value from being consumed, so this is not a data leak in the current control flow. It is still a validate-after-use ordering bug: up to 4 bytes are read past the end of the buffer before it is known to contain them, and it is fragile to future changes in the callers. Fix it at the source. Pass the end of the buffer into l2cap_get_conf_opt() and refuse to touch opt->val unless the full option (header + value) fits. Each caller computes an end pointer once before the loop and checks the return value directly instead of inferring the error from a negative length.

Announced Source revision 1
Original source ↗

CVE-2026-64403

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-64403

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "7c9cbd0b5e38a1672fcd137894ace3b042dfbf69",
        "lessThan": "cca81b4bc672604a84f6d224a55cc77ec7dee619",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7c9cbd0b5e38a1672fcd137894ace3b042dfbf69",
        "lessThan": "f70d4aa88068096f35d73e3a05eff33c0a16b9cd",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7c9cbd0b5e38a1672fcd137894ace3b042dfbf69",
        "lessThan": "7d871e969b941ce25653f7716203a0ea4d07ad4b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7c9cbd0b5e38a1672fcd137894ace3b042dfbf69",
        "lessThan": "98d93c226bdfaa79bbdd86981921d7f106374225",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "996d3da39899aceb8f4910911a3f19a45a7d9d1b",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "73abbaf91aa33da87c008fb62c148ade561bb606",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7c9cbd0b5e38a1672fcd137894ace3b042dfbf69",
        "lessThan": "6b47bdaacfd0045687880177e0987055d8f4765a",
        "versionType": "git"
      },
      {
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        "versionType": "git"
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      {
        "status": "affected",
        "version": "78c2887130f1a7d1883195732be1b6cdab667487",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ac7c597c465eb09391e40febbe088bdad601080b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ade4560e4fea198866e033fe1c02f063d6d7db2e",
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      {
        "status": "affected",
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      {
        "status": "affected",
        "version": "2b59d36f22622c92c0b06aee7571f0a86a217188",
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      {
        "status": "affected",
        "version": "15d6538a0d6e0f6de5116081a948cba7cc3e1d3d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a556547bae00528f24b42786b41a14047db14b84",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "3.16.66",
        "lessThan": "3.17",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "3.18.138",
        "lessThan": "3.19",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "4.4.178",
        "lessThan": "4.5",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "4.9.167",
        "lessThan": "4.10",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "4.14.110",
        "lessThan": "4.15",
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      },
      {
        "status": "affected",
        "version": "4.19.33",
        "lessThan": "4.20",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "5.0.6",
        "lessThan": "5.1",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "net/bluetooth/l2cap_core.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.1"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.1",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.261",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.212",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.178",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.96",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.39",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.4",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/bluetooth/l2cap_core.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-64403

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#41032 · Revision 1
Added to Heist Feed
Publisher date
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