In the Linux kernel, the following vulnerability has been resolved:
usb: xhci: Fix sleep in atomic context in xhci_free_streams()
When a USB device with active stream endpoints is disconnected,
xhci_free_streams() is called from the hub_event workqueue to
free the stream resources. It calls xhci_free_stream_info()
while holding xhci->lock with irqs disabled.
xhci_free_stream_info() invokes xhci_free_stream_ctx(), which
calls dma_free_coherent() for large stream context arrays.
dma_free_coherent() can sleep (e.g. via vunmap), triggering
a BUG when called from atomic context.
Call trace:
dma_free_attrs+0x174/0x220
xhci_free_stream_info+0xd0/0x11c
xhci_free_streams+0x278/0x37c
usb_free_streams+0x98/0xc0
usb_unbind_interface+0x1b8/0x2f8
device_release_driver_internal+0x1d4/0x2cc
device_release_driver+0x18/0x28
bus_remove_device+0x160/0x1a4
device_del+0x1ec/0x350
usb_disable_device+0x98/0x214
usb_disconnect+0xf0/0x35c
hub_event+0xab4/0x19ec
process_one_work+0x278/0x63c
Fix this by saving the stream_info pointers and clearing the
ep references under the lock, then calling xhci_free_stream_info()
outside the lock where sleeping is allowed.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
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.
The score's inputs: 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