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CVE-2026-72146
dmaengine: sh: rz-dmac: Move interrupt request after everything is set up
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/dma. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-72146 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.101-1 | Update the kernel and reboot. Fixed in 6.12.101-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4745-1 · 2026-08-18 · text | 6.12.101-1~deb12u1 | Update the kernel and reboot. DLA-4745-1 shipped the fix on 2026-08-18, in 6.12.101-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Once the interrupt is requested, the interrupt handler may run immediately. Since the IRQ handler can access channel->ch_base, which is initialized only after requesting the IRQ, this may lead to invalid memory access. Likewise, the IRQ thread may access uninitialized data (the ld_free, ld_queue, and ld_active lists), which may also lead to issues. Request the interrupts only after everything is set up. To keep the error path simpler, use dmam_alloc_coherent() instead of dma_alloc_coherent().
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/dma/sh/rz-dmac.c
- What this is
- DMA GENERIC OFFLOAD ENGINE SUBSYSTEMMAINTAINERS section matched on drivers/dma/ · dmaengine@vger.kernel.org · Maintained
- Kernel module
- none to look for. The file would have gone into rz_dmac, and Debian does not compile it into that module, so finding rz_dmac in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_DMADEVICES|CONFIG_RENESAS_DMA|CONFIG_RZ_DMAC' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
Show whether Debian builds this, per release
Debian does not build this code. In 5 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sid, bookworm · linux-6.12n
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_DMADEVICES, CONFIG_RENESAS_DMA, CONFIG_RZ_DMAC
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.18%, higher than 7.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/dma
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.15 | 5.15.216 | d24d53323e81 |
| 5.15 | 6.1.183 | 0e0c5b3cf374 |
| 5.15 | 6.6.148 | 5b12de6229d6 |
| 5.15 | 6.12.101 | 2a4d9e2234c3 |
| 5.15 | 6.18.42 | ec9f66c91bff |
| 5.15 | 7.1.5 | 07ae600bd353 |
| 5.15 | 7.2 | 731712403ddb |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DLA-4745-1 | 2026-08-18 | bookworm 6.12.101-1~deb12u1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The flaw triggers in rz_dmac_chan_probe() during Renesas RZ/G2L/V2H/T2H platform DMAC driver initialization at boot or module load; there is no network, Bluetooth, or runtime syscall path to the vulnerable devm_request_threaded_irq() ordering.
- AC:LAttack complexity, low
- Once the DMAC channel IRQ line is asserted when devm_request_threaded_irq() is called after reset_deassert, the hardirq/thread handlers run immediately before ch_base or lists are initialized; stale post-reset interrupt state on these SoCs makes this timing plausible without luck.
- PR:NPrivileges required, none
- rz_dmac_probe() performs no capability or authentication checks before requesting per-channel IRQs; on affected Renesas embedded boards the vulnerable probe sequence runs automatically during kernel boot without the attacker holding Linux privileges.
- UI:NUser interaction, none
- No victim action is required; pending/latched DMAC channel interrupts during driver probe at boot or reboot can invoke the buggy handlers without anyone opening device nodes or configuring DMA transfers.
- S:UScope, unchanged
- Impact is kernel NULL dereference, list/spinlock corruption, and MMIO faults within the host kernel; this is not a VM escape, container sandbox breakout, or documented IOMMU security-boundary bypass.
- C:HConfidentiality impact, high
- The threaded IRQ handler may lock an uninitialized vc.lock and walk uninitialized ld_active/ld_queue/ld_free lists, causing invalid kernel memory reads and list-metadata exposure beyond a pure bounded fault.
- I:HIntegrity impact, high
- The hardirq path issues readl/writel through uninitialized ch_base (NULL/low MMIO), and list/spinlock corruption in the IRQ thread can corrupt kernel heap metadata and enable control-flow hijack primitives.
- A:HAvailability impact, high
- Invalid MMIO via NULL ch_base and corrupted IRQ-thread list handling can cause kernel oops/panic during probe on affected embedded systems, causing full loss of availability until reboot.