Bluetooth: RFCOMM: Fix initial port reference race

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Summary

CVECVE-2026-98739
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-18 16:17:27 UTC
Updated2026-10-21 13:21:41 UTC
DescriptionIn 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 changes RFCOMM_TTY_OWNED from clear to set drops the initial reference. Each path keeps its own lookup reference until release or TTY cleanup, preserving the existing callback ordering and error handling.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 80ea73378af46b0023eb2f400d26c2a60248ffaa 55d162aa00d1ee33c3e6fa88b71f1e2d6e1441e9 git Not specified
CNA Linux Linux affected 80ea73378af46b0023eb2f400d26c2a60248ffaa a03ccf1ab77380d4c4a3c56552e12de4a83efa21 git Not specified
CNA Linux Linux affected 80ea73378af46b0023eb2f400d26c2a60248ffaa 0a554901bd227537f79220443b2b36d585d62893 git Not specified
CNA Linux Linux affected 80ea73378af46b0023eb2f400d26c2a60248ffaa e5aa7fbf7a4446bb89f0b8394b2dfc1a6b6aba5b git Not specified
CNA Linux Linux affected 80ea73378af46b0023eb2f400d26c2a60248ffaa 2d696c1ed3468dcb62578a3911e687110d463520 git Not specified
CNA Linux Linux affected 3.15 Not specified
CNA Linux Linux unaffected 3.15 semver Not specified
CNA Linux Linux unaffected 6.6.160 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.113 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.56 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.10 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/2d696c1ed3468dcb62578a3911e687110d463520 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0a554901bd227537f79220443b2b36d585d62893 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e5aa7fbf7a4446bb89f0b8394b2dfc1a6b6aba5b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a03ccf1ab77380d4c4a3c56552e12de4a83efa21 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/55d162aa00d1ee33c3e6fa88b71f1e2d6e1441e9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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