In the Linux kernel, the following vulnerability has been resolved:
bluetooth/l2cap: sync sock recv cb and release
The problem occurs between the system call to close the sock and hci_rx_work,
where the former releases the sock and the latter accesses it without lock protection.
CPU0 CPU1
---- ----
sock_close hci_rx_work
l2cap_sock_release hci_acldata_packet
l2cap_sock_kill l2cap_recv_frame
sk_free l2cap_conless_channel
l2cap_sock_recv_cb
If hci_rx_work processes the data that needs to be received before the sock is
closed, then everything is normal; Otherwise, the work thread may access the
released sock when receiving data.
Add a chan mutex in the rx callback of the sock to achieve synchronization between
the sock release and recv cb.
Sock is dead, so set chan data to NULL, avoid others use invalid sock pointer.
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it