In the Linux kernel, the following vulnerability has been resolved:
HID: hyperv: streamline driver probe to avoid devres issues
It was found that unloading 'hid_hyperv' module results in a devres
complaint:
...
hv_vmbus: unregistering driver hid_hyperv
------------[ cut here ]------------
WARNING: CPU: 2 PID: 3983 at drivers/base/devres.c:691 devres_release_group+0x1f2/0x2c0
...
Call Trace:
? devres_release_group+0x1f2/0x2c0
? __warn+0xd1/0x1c0
? devres_release_group+0x1f2/0x2c0
? report_bug+0x32a/0x3c0
? handle_bug+0x53/0xa0
? exc_invalid_op+0x18/0x50
? asm_exc_invalid_op+0x1a/0x20
? devres_release_group+0x1f2/0x2c0
? devres_release_group+0x90/0x2c0
? rcu_is_watching+0x15/0xb0
? __pfx_devres_release_group+0x10/0x10
hid_device_remove+0xf5/0x220
device_release_driver_internal+0x371/0x540
? klist_put+0xf3/0x170
bus_remove_device+0x1f1/0x3f0
device_del+0x33f/0x8c0
? __pfx_device_del+0x10/0x10
? cleanup_srcu_struct+0x337/0x500
hid_destroy_device+0xc8/0x130
mousevsc_remove+0xd2/0x1d0 [hid_hyperv]
device_release_driver_internal+0x371/0x540
driver_detach+0xc5/0x180
bus_remove_driver+0x11e/0x2a0
? __mutex_unlock_slowpath+0x160/0x5e0
vmbus_driver_unregister+0x62/0x2b0 [hv_vmbus]
...
And the issue seems to be that the corresponding devres group is not
allocated. Normally, devres_open_group() is called from
__hid_device_probe() but Hyper-V HID driver overrides 'hid_dev->driver'
with 'mousevsc_hid_driver' stub and basically re-implements
__hid_device_probe() by calling hid_parse() and hid_hw_start() but not
devres_open_group(). hid_device_probe() does not call __hid_device_probe()
for it. Later, when the driver is removed, hid_device_remove() calls
devres_release_group() as it doesn't check whether hdev->driver was
initially overridden or not.
The issue seems to be related to the commit 62c68e7cee33 ("HID: ensure
timely release of driver-allocated resources") but the commit itself seems
to be correct.
Fix the issue by dropping the 'hid_dev->driver' override and using
hid_register_driver()/hid_unregister_driver() instead. Alternatively, it
would have been possible to rely on the default handling but
HID_CONNECT_DEFAULT implies HID_CONNECT_HIDRAW and it doesn't seem to work
for mousevsc as-is.
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.GitHub Security Advisory CVSS
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-05). 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