In the Linux kernel, the following vulnerability has been resolved:
phy: tegra: xusb: Use a bitmask for UTMI pad power state tracking
The current implementation uses bias_pad_enable as a reference count to
manage the shared bias pad for all UTMI PHYs. However, during system
suspension with connected USB devices, multiple power-down requests for
the UTMI pad result in a mismatch in the reference count, which in turn
produces warnings such as:
[ 237.762967] WARNING: CPU: 10 PID: 1618 at tegra186_utmi_pad_power_down+0x160/0x170
[ 237.763103] Call trace:
[ 237.763104] tegra186_utmi_pad_power_down+0x160/0x170
[ 237.763107] tegra186_utmi_phy_power_off+0x10/0x30
[ 237.763110] phy_power_off+0x48/0x100
[ 237.763113] tegra_xusb_enter_elpg+0x204/0x500
[ 237.763119] tegra_xusb_suspend+0x48/0x140
[ 237.763122] platform_pm_suspend+0x2c/0xb0
[ 237.763125] dpm_run_callback.isra.0+0x20/0xa0
[ 237.763127] __device_suspend+0x118/0x330
[ 237.763129] dpm_suspend+0x10c/0x1f0
[ 237.763130] dpm_suspend_start+0x88/0xb0
[ 237.763132] suspend_devices_and_enter+0x120/0x500
[ 237.763135] pm_suspend+0x1ec/0x270
The root cause was traced back to the dynamic power-down changes
introduced in commit a30951d31b25 ("xhci: tegra: USB2 pad power controls"),
where the UTMI pad was being powered down without verifying its current
state. This unbalanced behavior led to discrepancies in the reference
count.
To rectify this issue, this patch replaces the single reference counter
with a bitmask, renamed to utmi_pad_enabled. Each bit in the mask
corresponds to one of the four USB2 PHYs, allowing us to track each pad's
enablement status individually.
With this change:
- The bias pad is powered on only when the mask is clear.
- Each UTMI pad is powered on or down based on its corresponding bit
in the mask, preventing redundant operations.
- The overall power state of the shared bias pad is maintained
correctly during suspend/resume cycles.
The mutex used to prevent race conditions during UTMI pad enable/disable
operations has been moved from the tegra186_utmi_bias_pad_power_on/off
functions to the parent functions tegra186_utmi_pad_power_on/down. This
change ensures that there are no race conditions when updating the bitmask.
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