CVE-2025-38136
NoneCVSS
—
EPSS
0.2%
Published
Jul 3, 2025
CISA due date
—
Cloudanix analysis
A driver ordering mistake can crash certain Linux systems when USB hardware starts up, and fixing it requires updating the operating system kernel.
- Exploitation
- Local Privilege
- Attacker needs
- Local User
- Complexity
- Low
- Impact
- Denial Of Service
- Component
- OS kernel
- Class
- Other
- Remediation
- Upgrade
- Effort
- Medium
- Patch risk
- Low
What it actually does
The flaw performs register writes via usbhs_bset/usbhs_write before clocks are enabled in usbhs_probe, triggering synchronous external aborts on RZ/V2H hardware when iowrite16 executes against unclocked peripherals.
Why it matters to the business
Systems using the affected Renesas USBHS driver may crash during module load or device probe, causing boot failures, USB subsystem loss, and operational downtime on RZ/V2H-based platforms; high downstream kernel prevalence increases exposure across embedded and server distributions.
How an attack unfolds
An attacker loads or triggers the renesas_usbhs driver (via USB device insertion or module init) to reach usbhs_probe before runtime PM and clock acquisition complete; the resulting unclocked register access produces a kernel panic, usable for denial-of-service. Listed threat actors have targeted similar Linux kernel USB and privilege-escalation paths in related campaigns.
How to fix it
Update to a kernel containing commit 095cc0b5888acc228f12344e85b17539b9ce9367 or later stable release; enable runtime PM early in usbhs_probe and acquire clocks before any register access. For dotnet (Bitnami) environments, upgrade to 8.0.16 or newer containing the fix.
How to confirm the fix worked
Confirm the driver initializes without synchronous external abort logs on RZ/V2H hardware; verify the presence of the reorder patch by checking that usbhs_probe enables PM runtime before usbhs_sys_clock_ctrl; run module load and USB attach tests post-upgrade.
Typical attack path
- Insert USB device or trigger module load to invoke renesas_usbhs_driver_init
- platform_probe calls usbhs_probe without prior runtime PM enablement
- usbhs_sys_clock_ctrl invokes usbhs_bset before clocks are acquired
- iowrite16 executes against uninitialized hardware registers
- Synchronous external abort crashes the kernel
How to detect it
Search kernel logs for "synchronous external abort" combined with renesas_usbhs and usbhs_bset stack traces; inspect udev-worker or finit_module processes during USB initialization; review dmesg for RZ/V2H hardware panics matching the provided call trace. Correlate with any observed activity from the listed threat actors targeting Linux kernel privilege-escalation CVEs.
- usbhs_bset+0x14/0x4c [renesas_usbhs]
- Internal error: synchronous external abort: 0000000096000010
- renesas_usbhs(+) drm_kms_helper
- Modules linked in: cec renesas_usbhs
What your security team should do
- Prioritize kernel upgrades on all RZ/V2H and Renesas USBHS deployments within 30 days given the 481-day publication window and listed threat-actor interest
- Add kernel panic and usbhs_bset call traces to SIEM rules for immediate detection
- Test driver load in staging environments before production rollout
- Monitor EPSS trend (currently rising +8%) and reassess if new exploit code appears
The record
In the Linux kernel, the following vulnerability has been resolved: usb: renesas_usbhs: Reorder clock handling and power management in probe Reorder the initialization sequence in `usbhs_probe()` to enable runtime PM before accessing registers, preventing potential crashes due to uninitialized clocks. Currently, in the probe path, registers are accessed before enabling the clocks, leading to a synchronous external abort on the RZ/V2H SoC. The problematic call flow is as follows: usbhs_probe() usbhs_sys_clock_ctrl() usbhs_bset() usbhs_write() iowrite16() <-- Register access before enabling clocks Since `iowrite16()` is performed without ensuring the required clocks are enabled, this can lead to access errors. To fix this, enable PM runtime early in the probe function and ensure clocks are acquired before register access, preventing crashes like the following on RZ/V2H: [13.272640] Internal error: synchronous external abort: 0000000096000010 [#1] PREEMPT SMP [13.280814] Modules linked in: cec renesas_usbhs(+) drm_kms_helper fuse drm backlight ipv6 [13.289088] CPU: 1 UID: 0 PID: 195 Comm: (udev-worker) Not tainted 6.14.0-rc7+ #98 [13.296640] Hardware name: Renesas RZ/V2H EVK Board based on r9a09g057h44 (DT) [13.303834] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [13.310770] pc : usbhs_bset+0x14/0x4c [renesas_usbhs] [13.315831] lr : usbhs_probe+0x2e4/0x5ac [renesas_usbhs] [13.321138] sp : ffff8000827e3850 [13.324438] x29: ffff8000827e3860 x28: 0000000000000000 x27: ffff8000827e3ca0 [13.331554] x26: ffff8000827e3ba0 x25: ffff800081729668 x24: 0000000000000025 [13.338670] x23: ffff0000c0f08000 x22: 0000000000000000 x21: ffff0000c0f08010 [13.345783] x20: 0000000000000000 x19: ffff0000c3b52080 x18: 00000000ffffffff [13.352895] x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000827e36ce [13.360009] x14: 00000000000003d7 x13: 00000000000003d7 x12: 0000000000000000 [13.367122] x11: 0000000000000000 x10: 0000000000000aa0 x9 : ffff8000827e3750 [13.374235] x8 : ffff0000c1850b00 x7 : 0000000003826060 x6 : 000000000000001c [13.381347] x5 : 000000030d5fcc00 x4 : ffff8000825c0000 x3 : 0000000000000000 [13.388459] x2 : 0000000000000400 x1 : 0000000000000000 x0 : ffff0000c3b52080 [13.395574] Call trace: [13.398013] usbhs_bset+0x14/0x4c [renesas_usbhs] (P) [13.403076] platform_probe+0x68/0xdc [13.406738] really_probe+0xbc/0x2c0 [13.410306] __driver_probe_device+0x78/0x120 [13.414653] driver_probe_device+0x3c/0x154 [13.418825] __driver_attach+0x90/0x1a0 [13.422647] bus_for_each_dev+0x7c/0xe0 [13.426470] driver_attach+0x24/0x30 [13.430032] bus_add_driver+0xe4/0x208 [13.433766] driver_register+0x68/0x130 [13.437587] __platform_driver_register+0x24/0x30 [13.442273] renesas_usbhs_driver_init+0x20/0x1000 [renesas_usbhs] [13.448450] do_one_initcall+0x60/0x1d4 [13.452276] do_init_module+0x54/0x1f8 [13.456014] load_module+0x1754/0x1c98 [13.459750] init_module_from_file+0x88/0xcc [13.464004] __arm64_sys_finit_module+0x1c4/0x328 [13.468689] invoke_syscall+0x48/0x104 [13.472426] el0_svc_common.constprop.0+0xc0/0xe0 [13.477113] do_el0_svc+0x1c/0x28 [13.480415] el0_svc+0x30/0xcc [13.483460] el0t_64_sync_handler+0x10c/0x138 [13.487800] el0t_64_sync+0x198/0x19c [13.491453] Code: 2a0103e1 12003c42 12003c63 8b010084 (79400084) [13.497522] ---[ end trace 0000000000000000 ]---
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Debian:11 | linux | 0 | No fix |
| Debian:12 | linux | 0 | No fix |
| Debian:13 | linux | 0 | No fix |
| Debian:14 | linux | 0 | 6.12.35-1 |
| Linux | Kernel | 3.0.0 | 5.4.295 |
| Mageia:9 | kernel | 0 | 6.6.101-1.mga9 |
| Mageia:9 | kernel-linus | 0 | 6.6.101-1.mga9 |
| Mageia:9 | kmod-virtualbox | 0 | 7.1.10-7.mga9 |
| Mageia:9 | kmod-xtables-addons | 0 | 3.24-83.mga9 |
| Mageia:9 | wireless-regdb | 0 | 20250710-1.mga9 |
| SUSE:Linux Enterprise High Availability Extension 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6-RT_Update_14 | 0 | 1-150600.1.5.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_14 | 0 | 1-150600.13.3.4 |
| SUSE:Linux Enterprise Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_3 | 0 | 1-150700.1.5.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-64kb | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-default-base | 0 | 6.4.0-150600.23.65.1.150600.12.28.4 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-source | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-zfcpdump | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-coco | 0 | 6.4.0-15061.28.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-coco_debug | 0 | 6.4.0-15061.28.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-source-coco | 0 | 6.4.0-15061.28.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-syms-coco | 0 | 6.4.0-15061.28.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-docs | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-obs-build | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-source | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-syms | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Legacy 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-azure | 0 | 6.4.0-150600.8.48.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-source-azure | 0 | 6.4.0-150600.8.48.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-syms-azure | 0 | 6.4.0-150600.8.48.1 |
| SUSE:Linux Enterprise Workstation Extension 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.65.1 |
| SUSE:Real Time Module 15 SP6 | kernel-rt | 0 | 6.4.0-150600.10.49.1 |
| SUSE:Real Time Module 15 SP6 | kernel-rt_debug | 0 | 6.4.0-150600.10.49.1 |
| SUSE:Real Time Module 15 SP6 | kernel-source-rt | 0 | 6.4.0-150600.10.49.1 |
| SUSE:Real Time Module 15 SP6 | kernel-syms-rt | 0 | 6.4.0-150600.10.49.1 |
| SUSE:Real Time Module 15 SP7 | kernel-rt | 0 | 6.4.0-150700.7.13.1 |
| SUSE:Real Time Module 15 SP7 | kernel-source-rt | 0 | 6.4.0-150700.7.13.1 |
| SUSE:Real Time Module 15 SP7 | kernel-syms-rt | 0 | 6.4.0-150700.7.13.1 |
| openSUSE:Leap 15.6 | dtb-aarch64 | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-64kb | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-azure | 0 | 6.4.0-150600.8.48.1 |
| openSUSE:Leap 15.6 | kernel-debug | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-default | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-default-base | 0 | 6.4.0-150600.23.65.1.150600.12.28.4 |
| openSUSE:Leap 15.6 | kernel-docs | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-kvmsmall | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-obs-build | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-obs-qa | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-rt | 0 | 6.4.0-150600.10.49.1 |
| openSUSE:Leap 15.6 | kernel-rt_debug | 0 | 6.4.0-150600.10.49.1 |
| openSUSE:Leap 15.6 | kernel-source | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-source-azure | 0 | 6.4.0-150600.8.48.1 |
| openSUSE:Leap 15.6 | kernel-source-rt | 0 | 6.4.0-150600.10.49.1 |
| openSUSE:Leap 15.6 | kernel-syms | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 15.6 | kernel-syms-azure | 0 | 6.4.0-150600.8.48.1 |
| openSUSE:Leap 15.6 | kernel-syms-rt | 0 | 6.4.0-150600.10.49.1 |
| openSUSE:Leap 15.6 | kernel-zfcpdump | 0 | 6.4.0-150600.23.65.1 |
| openSUSE:Leap 16.0 | dtb-aarch64 | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-64kb | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-default | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-default-base | 0 | 6.12.0-160000.6.1.160000.2.4 |
| openSUSE:Leap 16.0 | kernel-docs | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-kvmsmall | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-obs-build | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-obs-qa | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-rt | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-source | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-syms | 0 | 6.12.0-160000.6.1 |
| openSUSE:Leap 16.0 | kernel-zfcpdump | 0 | 6.12.0-160000.6.1 |
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