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Advisory severityMedium4.8Red Hat Linux

Medium [CVE-2026-63871] Fix data-race on iso_pi fields in hci_get_route calls

This medium-severity Red Hat Linux advisory covers CVE-2026-63871 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat package: kernel.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-63871 Source published Source updated

VulniPulse record published Record updated

CVE-2026-63871
Affected products & platforms
Red Hat LinuxLinux Kernel
Open source advisory

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Summary

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: Fix data-race on iso_pi fields in hci_get_route calls iso_connect_bis(), iso_connect_cis(), iso_listen_bis(), and iso_conn_big_sync() call hci_get_route() using iso_pi(sk)->dst, iso_pi(sk)->src, and iso_pi(sk)->src_type without holding lock_sock().

These fields may be modified concurrently by connect() or setsockopt() on the same socket, resulting in data-races reported by KCSAN. Fix this by snapshotting the required fields under lock_sock() before calling hci_get_route().

BUG: KCSAN: data-race in memcmp+0x45/0xb0 race at unknown origin, with read to 0xffff8880122135cf of 1 bytes by task 333 on cpu 1: memcmp+0x45/0xb0 hci_get_route+0x27e/0x490 iso_connect_cis+0x4c/0xa10 iso_sock_connect+0x60e/0xb30 __sys_connect_file+0xbd/0xe0 __sys_connect+0xe0/0x110 __x64_sys_connect+0x40/0x50 x64_sys_call+0xcad/0x1c60 do_syscall_64+0x133/0x590 entry_SYSCALL_64_after_hwframe+0x77/0x7f This vulnerability, a data-race, occurs because certain functions access socket-related data without proper synchronization.

Specifically, iso_connect_bis(), iso_connect_cis(), iso_listen_bis(), and iso_conn_big_sync() can read critical fields while they are being modified by other operations like connect() or setsockopt(). This concurrent access can lead to unpredictable system behavior and potential integrity issues.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · medium-confidence parse· fetched 7 days ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.

Official advisory · medium-confidence parse· fetched 7 days ago·verify at source

Mitigation

The source record does not include mitigation steps. That does not mean no fix exists. Read the vendor advisory below for the authoritative guidance.

Official advisory · medium-confidence parse· fetched 7 days ago·verify at source

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