{"id":"CVE-2026-98739","state":"PUBLISHED","title":"Bluetooth: RFCOMM: Fix initial port reference race","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: Fix initial port reference race\n\nFor RFCOMM_RELEASE_ONHUP devices, rfcomm_tty_install() and\n__rfcomm_release_dev() both use RFCOMM_TTY_OWNED to decide who drops the\ninitial tty_port reference. The release path tests the bit separately\nfrom the install path setting it, so both can drop that reference.\n\nThe synchronous hangup does not prevent this race: port->tty is not\nassigned until tty_port_open(), after installation. The following\ninterleaving is possible:\n\n  1. Install and release each obtain a reference with rfcomm_dev_get().\n  2. Release observes RFCOMM_TTY_OWNED clear.\n  3. Install sets RFCOMM_TTY_OWNED and drops the initial reference.\n  4. Release drops the same initial reference again.\n  5. TTY cleanup drops its reference and frees the device.\n  6. Release performs its final tty_port_put() on the freed port.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in tty_port_put+0x22/0x190\n  Write of size 4 at addr ffff8881001d3d5c by task poc/92\n\n  Call Trace:\n   tty_port_put+0x22/0x190\n   rfcomm_dev_ioctl+0x1d4/0x1930\n   sock_do_ioctl+0x110/0x260\n   sock_ioctl+0x380/0x590\n   __x64_sys_ioctl+0x134/0x1c0\n\n  Allocated by task 88:\n   rfcomm_dev_ioctl+0x8f6/0x1930\n   sock_do_ioctl+0x110/0x260\n   sock_ioctl+0x380/0x590\n   __x64_sys_ioctl+0x134/0x1c0\n\n  Freed by task 65:\n   kfree+0x131/0x3c0\n   rfcomm_dev_destruct+0x23b/0x2f0\n   release_one_tty+0xc1/0x370\n   process_one_work+0x661/0x1090\n\nUse test_and_set_bit() in both paths so that only the caller that changes\nRFCOMM_TTY_OWNED from clear to set drops the initial reference. Each path\nkeeps its own lookup reference until release or TTY cleanup, preserving\nthe existing callback ordering and error handling.","publishedAt":"2026-10-18T15:47:23.653Z","updatedAt":"2026-10-30T12:39:14.099Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"cd247e38b14df48d6b3940c4573a9f7acb10c363","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"d3dd18e85c140df72e0f2b5ee156ebfba04c06cb","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"c50360a019766fafa27318928bfea96dcce8a37d","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"55d162aa00d1ee33c3e6fa88b71f1e2d6e1441e9","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"a03ccf1ab77380d4c4a3c56552e12de4a83efa21","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"0a554901bd227537f79220443b2b36d585d62893","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"e5aa7fbf7a4446bb89f0b8394b2dfc1a6b6aba5b","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"2d696c1ed3468dcb62578a3911e687110d463520","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/rfcomm/tty.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.15","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/rfcomm/tty.c"]}],"references":["https://git.kernel.org/stable/c/cd247e38b14df48d6b3940c4573a9f7acb10c363","https://git.kernel.org/stable/c/d3dd18e85c140df72e0f2b5ee156ebfba04c06cb","https://git.kernel.org/stable/c/c50360a019766fafa27318928bfea96dcce8a37d","https://git.kernel.org/stable/c/55d162aa00d1ee33c3e6fa88b71f1e2d6e1441e9","https://git.kernel.org/stable/c/a03ccf1ab77380d4c4a3c56552e12de4a83efa21","https://git.kernel.org/stable/c/0a554901bd227537f79220443b2b36d585d62893","https://git.kernel.org/stable/c/e5aa7fbf7a4446bb89f0b8394b2dfc1a6b6aba5b","https://git.kernel.org/stable/c/2d696c1ed3468dcb62578a3911e687110d463520"],"weaknesses":[],"ingestedAt":"2026-10-30T12:58:04.520Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98739.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98739","state":"PUBLISHED","datePublished":"2026-10-18T15:47:23.653Z","dateUpdated":"2026-10-30T12:39:14.099Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.367Z"},"containers":{"cna":{"title":"Bluetooth: RFCOMM: Fix initial port reference race","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: Fix initial port reference race\n\nFor RFCOMM_RELEASE_ONHUP devices, rfcomm_tty_install() and\n__rfcomm_release_dev() both use RFCOMM_TTY_OWNED to decide who drops the\ninitial tty_port reference. The release path tests the bit separately\nfrom the install path setting it, so both can drop that reference.\n\nThe synchronous hangup does not prevent this race: port->tty is not\nassigned until tty_port_open(), after installation. The following\ninterleaving is possible:\n\n  1. Install and release each obtain a reference with rfcomm_dev_get().\n  2. Release observes RFCOMM_TTY_OWNED clear.\n  3. Install sets RFCOMM_TTY_OWNED and drops the initial reference.\n  4. Release drops the same initial reference again.\n  5. TTY cleanup drops its reference and frees the device.\n  6. Release performs its final tty_port_put() on the freed port.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in tty_port_put+0x22/0x190\n  Write of size 4 at addr ffff8881001d3d5c by task poc/92\n\n  Call Trace:\n   tty_port_put+0x22/0x190\n   rfcomm_dev_ioctl+0x1d4/0x1930\n   sock_do_ioctl+0x110/0x260\n   sock_ioctl+0x380/0x590\n   __x64_sys_ioctl+0x134/0x1c0\n\n  Allocated by task 88:\n   rfcomm_dev_ioctl+0x8f6/0x1930\n   sock_do_ioctl+0x110/0x260\n   sock_ioctl+0x380/0x590\n   __x64_sys_ioctl+0x134/0x1c0\n\n  Freed by task 65:\n   kfree+0x131/0x3c0\n   rfcomm_dev_destruct+0x23b/0x2f0\n   release_one_tty+0xc1/0x370\n   process_one_work+0x661/0x1090\n\nUse test_and_set_bit() in both paths so that only the caller that changes\nRFCOMM_TTY_OWNED from clear to set drops the initial reference. Each path\nkeeps its own lookup reference until release or TTY cleanup, preserving\nthe existing callback ordering and error handling."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"cd247e38b14df48d6b3940c4573a9f7acb10c363","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"d3dd18e85c140df72e0f2b5ee156ebfba04c06cb","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"c50360a019766fafa27318928bfea96dcce8a37d","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"55d162aa00d1ee33c3e6fa88b71f1e2d6e1441e9","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"a03ccf1ab77380d4c4a3c56552e12de4a83efa21","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"0a554901bd227537f79220443b2b36d585d62893","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"e5aa7fbf7a4446bb89f0b8394b2dfc1a6b6aba5b","versionType":"git"},{"version":"80ea73378af46b0023eb2f400d26c2a60248ffaa","status":"affected","lessThan":"2d696c1ed3468dcb62578a3911e687110d463520","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/rfcomm/tty.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.15","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/rfcomm/tty.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/cd247e38b14df48d6b3940c4573a9f7acb10c363"},{"url":"https://git.kernel.org/stable/c/d3dd18e85c140df72e0f2b5ee156ebfba04c06cb"},{"url":"https://git.kernel.org/stable/c/c50360a019766fafa27318928bfea96dcce8a37d"},{"url":"https://git.kernel.org/stable/c/55d162aa00d1ee33c3e6fa88b71f1e2d6e1441e9"},{"url":"https://git.kernel.org/stable/c/a03ccf1ab77380d4c4a3c56552e12de4a83efa21"},{"url":"https://git.kernel.org/stable/c/0a554901bd227537f79220443b2b36d585d62893"},{"url":"https://git.kernel.org/stable/c/e5aa7fbf7a4446bb89f0b8394b2dfc1a6b6aba5b"},{"url":"https://git.kernel.org/stable/c/2d696c1ed3468dcb62578a3911e687110d463520"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:39:14.099Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.15","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.15","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.15","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.15","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.15","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.15","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.15","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.15","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}