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no cvss —

CVE-2026-98738 json

Bluetooth: Serialize SMP remote OOB data access

published 24d ago modified 21d ago also EUVD-2026-103823

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: Serialize SMP remote OOB data access

build_pairing_cmd() looks up remote OOB data and copies its contents without holding hdev->lock, which serializes the list's writers. After SMP finds an entry, a concurrent management Remove Remote OOB Data command can unlink and free it before SMP reads its present flag or copies its random and confirmation values. Removal can also invalidate an entry while the lookup is still traversing the list.

KASAN reported:

BUG: KASAN: slab-use-after-free in build_pairing_cmd+0x948/0x9b0 Call Trace: build_pairing_cmd+0x948/0x9b0 smp_recv_cb+0x459f/0x8110 l2cap_recv_frame+0xf14/0x9190 l2cap_recv_acldata+0xa64/0xd40 hci_rx_work+0x4ca/0x730

Allocated by task 87: hci_add_remote_oob_data+0x11d/0x530 add_remote_oob_data+0x282/0x400 hci_sock_sendmsg+0x1033/0x1ea0

Freed by task 93: hci_remote_oob_data_clear+0x108/0x1c0 remove_remote_oob_data+0x198/0x220 hci_sock_sendmsg+0x1033/0x1ea0

Taking hdev->lock in build_pairing_cmd() would recurse for callers that already hold it and invert the device-to-L2CAP lock order on the receive path. Add a per-device remote_oob_lock instead, held across the SMP lookup and copies and by the add, remove and clear helpers. Cover initialization and in-place updates as well, so SMP cannot read partially initialized or updated OOB values. Release the mutex on allocation failure, preserving the existing error return.

The new critical sections acquire no device, connection or channel locks. Writers retain their existing hdev->lock protection, which continues to serialize the other readers without changing their locking or behavior.

Patch / fix

  • Linux Linux 7.3
  • linux Debian 13 6.12.113-1
  • linux Debian 14 7.2.10-1
  • linux-6.12 Debian 12 6.12.113-1~deb12u1

debian advisories DEBIAN-CVE-2026-98738

  • linux Ubuntu 24.04 LTS 6.8.0-149.149
  • linux Ubuntu 26.04 LTS 7.0.0-43.43
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1069.74
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1017.18
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1073.81
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1017.19
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1068.77
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1010.11

ubuntu advisories UBUNTU-CVE-2026-98738

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel Azure Linux 3.0 6.6.161.1-1

azure linux advisories AZL-108674

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-98738 updated cvss 5.1

kernel: kernel: denial of service via race condition in Bluetooth SMP remote OOB handling

  • Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-11).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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