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Bluetooth: RFCOMM: Fix initial port reference race

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: Fix initial port reference race For RFCOMM_RELEASE_ONHUP devices, rfcomm_tty_install() and __rfcomm_release_dev() both use RFCOMM_TTY_OWNED to decide who drops the initial tty_port reference. The release path tests the bit separately from the install path setting it, so both can drop that reference. The synchronous hangup does not prevent this race: port->tty is not assigned until tty_port_open(), after installation. The following interleaving is possible: 1. Install and release each obtain a reference with rfcomm_dev_get(). 2. Release observes RFCOMM_TTY_OWNED clear. 3. Install sets RFCOMM_TTY_OWNED and drops the initial reference. 4. Release drops the same initial reference again. 5. TTY cleanup drops its reference and frees the device. 6. Release performs its final tty_port_put() on the freed port. KASAN reported: BUG: KASAN: slab-use-after-free in tty_port_put+0x22/0x190 Write of size 4 at addr ffff8881001d3d5c by task poc/92 Call Trace: tty_port_put+0x22/0x190 rfcomm_dev_ioctl+0x1d4/0x1930 sock_do_ioctl+0x110/0x260 sock_ioctl+0x380/0x590 __x64_sys_ioctl+0x134/0x1c0 Allocated by task 88: rfcomm_dev_ioctl+0x8f6/0x1930 sock_do_ioctl+0x110/0x260 sock_ioctl+0x380/0x590 __x64_sys_ioctl+0x134/0x1c0 Freed by task 65: kfree+0x131/0x3c0 rfcomm_dev_destruct+0x23b/0x2f0 release_one_tty+0xc1/0x370 process_one_work+0x661/0x1090 Use test_and_set_bit() in both paths so that only the caller that change

Announced Source revision 1
Original source ↗

CVE-2026-98739

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-2026-98739

Linux

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

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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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": "80ea73378af46b0023eb2f400d26c2a60248ffaa",
        "lessThan": "55d162aa00d1ee33c3e6fa88b71f1e2d6e1441e9",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "80ea73378af46b0023eb2f400d26c2a60248ffaa",
        "lessThan": "a03ccf1ab77380d4c4a3c56552e12de4a83efa21",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "80ea73378af46b0023eb2f400d26c2a60248ffaa",
        "lessThan": "0a554901bd227537f79220443b2b36d585d62893",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "80ea73378af46b0023eb2f400d26c2a60248ffaa",
        "lessThan": "e5aa7fbf7a4446bb89f0b8394b2dfc1a6b6aba5b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "80ea73378af46b0023eb2f400d26c2a60248ffaa",
        "lessThan": "2d696c1ed3468dcb62578a3911e687110d463520",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/bluetooth/rfcomm/tty.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.15"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.15",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.113",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.56",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.10",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/bluetooth/rfcomm/tty.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98739

Source reference: /cveMetadata/cveId

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Event
#48938 · Revision 1
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