CVE-2026-98738: Linux Vulnerability

Description

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.

Metrics

EPSS Probability

0.17%

5.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 02b05bd8b0a632e9a26795bced8f19ca6a5f7079, < 94afa17d6bfd5c1d367c56c8b63df5f695380861; >= 02b05bd8b0a632e9a26795bced8f19ca6a5f7079, < 1e11412a1b9854a89d044576d616675b16141d87; >= 02b05bd8b0a632e9a26795bced8f19ca6a5f7079, < 889c61e3d0f1091a958e4b2a24b20bab23d915c4; >= 02b05bd8b0a632e9a26795bced8f19ca6a5f7079, < df5162eeb10e69fe0c2349503882c4a09077f001; >= 02b05bd8b0a632e9a26795bced8f19ca6a5f7079, < 81a2345f1984f0b36d3226571bc196316a01b648
Linux	Linux	3.19

References

Timeline

Published: Oct 18, 2026
Last Modified: Oct 21, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-98738?

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.

How severe is CVE-2026-98738?

Severity scoring for CVE-2026-98738 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2026-98738?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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