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CVE-2026-72149
dmaengine: tegra: Fix burst size calculation
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-2026-72149 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 | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. 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. |
The vulnerability
What the bug is
Currently, the Tegra GPC DMA hardware requires the transfer length to be a multiple of the max burst size configured for the channel. When a client requests a transfer where the length is not evenly divisible by the configured max burst size, the DMA hangs with partial burst at the end. Fix this by reducing the burst size to the largest power-of-2 value that evenly divides the transfer length. For example, a 40-byte transfer with a 16-byte max burst will now use an 8-byte burst (40 / 8 = 5 complete bursts) instead of causing a hang. This issue was observed with the PL011 UART driver where TX DMA transfers of arbitrary lengths were stuck.
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/tegra186-gpc-dma.c
- What this is
- TEGRA DMA DRIVERSMAINTAINERS section matched on drivers/dma/tegra* · Supported
- Kernel module
- none to look for. The file would have gone into tegra186_gpc_dma, and Debian does not compile it into that module, so finding tegra186_gpc_dma in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_DMADEVICES|CONFIG_TEGRA186_GPC_DMA' /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 4 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, sidn
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_DMADEVICES, CONFIG_TEGRA186_GPC_DMA
- 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
- 7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.65%, higher than 50.0% 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 |
|---|---|---|
| 5.19 | 6.1.178 | 735951baa311 |
| 5.19 | 6.6.145 | 8f0f5de10911 |
| 5.19 | 6.12.97 | a3b76b54e06d |
| 5.19 | 6.18.40 | 7926c1e4be86 |
| 5.19 | 7.1.5 | 6e37e9e230c7 |
| 5.19 | 7.2 | 4651df83b6c7 |
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:NAttack vector, network
- On Tegra embedded systems (Jetson gateways, automotive ECUs, industrial controllers), UART/I2C/SPI slaves using GPC DMA are routinely bridged to TCP/UDP or cellular backhaul; remote peers can deliver crafted-length byte streams that reach tegra_dma_prep_slave_sg() without local shell access.
- AC:LAttack complexity, low
- The attacker controls transfer length (e.g., 40 bytes against a 16-byte burst); word-aligned mismatches are deterministic for many sizes and the bug was reproduced with arbitrary PL011 TX DMA lengths, requiring no race, timing window, or special memory layout.
- PR:NPrivileges required, none
- Network-exposed serial/fieldbus gateways and modem UART paths routinely accept unauthenticated remote traffic forwarded into kernel DMA slave transfers; no local OS account, dialout membership, or root capability on the Tegra host is required.
- UI:NUser interaction, none
- Exploitation requires only attacker-supplied I/O of a chosen length through an exposed peripheral path; no victim must open a device, mount media, or perform any other action.
- S:UScope, unchanged
- The DMA engine hang and resulting peripheral denial occur entirely within the host kernel; no VM, hypervisor, or IOMMU security boundary is crossed.
- C:NConfidentiality impact, none
- The flaw is a hardware DMA configuration hang with no out-of-bounds access, use-after-free, or information leak; the controller stalls on a partial burst without exposing kernel memory contents.
- I:NIntegrity impact, none
- No memory corruption or attacker-controlled writes occur; impact is limited to stalling DMA completion and hanging the affected channel/peripheral rather than modifying data or hijacking control flow.
- A:HAvailability impact, high
- A mismatched burst leaves the GPC DMA channel permanently busy (tegra_dma_pause() times out, no EOC IRQ), wedging UART/I2C/SPI DMA paths and blocking driver completion until reboot—a deadlock-style denial of service.