In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7921/mt7925: fix NULL dereference in CSA beacon
This patch is based on a BUG as reported by Bongani Hlope at
https://lore.kernel.org/all/[email protected]/
When a channel-switch announcement (CSA) beacon is received,
cfg80211 queues a wiphy work item that eventually calls
mt7921_channel_switch_rx_beacon(). If the station disconnects
(or the channel context is otherwise torn down) between the
time the work is queued and the time it runs, the driver's
dev->new_ctx pointer can already have been cleared to NULL.
mt7921_channel_switch_rx_beacon() then dereferences new_ctx
unconditionally, triggering a NULL pointer dereference at
address 0x0:
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:mt7921_channel_switch_rx_beacon+0x1f/0x100 [mt7921_common]
The same missing guard exists in mt7925_channel_switch_rx_beacon(),
which shares the same code pattern introduced by the same commit.
Add an early-return NULL check for dev->new_ctx in both
mt7921_channel_switch_rx_beacon() and
mt7925_channel_switch_rx_beacon(). When new_ctx is NULL there is
no pending channel switch to process, so returning immediately is
the correct and safe action.
Oops-Analysis: http://oops.fenrus.org/reports/lkml/[email protected]/report.html
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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)14 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's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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