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CVE-2026-68466
mtd: rawnand: lpc32xx_slc: fail DMA transfer on completion timeout
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/mtd. 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-2026-68466 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
lpc32xx_xmit_dma() waits for the DMA completion callback but ignores wait_for_completion_timeout(). A timed out DMA transfer is therefore unmapped and reported as successful to the NAND read/write path. Return -ETIMEDOUT when the completion wait expires. Terminate the DMA channel before unmapping the scatterlist so the timed out transfer cannot continue to access the buffer after the error is returned.
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/mtd/nand/raw/lpc32xx_slc.c
- What this is
- NAND FLASH SUBSYSTEMMAINTAINERS section matched on drivers/mtd/nand/ · linux-mtd@lists.infradead.org · Maintained
- Kernel module
- none to look for. The file would have gone into lpc32xx_slc, and Debian does not compile it into that module, so finding lpc32xx_slc in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_MTD|CONFIG_MTD_NAND_SLC_LPC32XX' /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_MTD, CONFIG_MTD_NAND_SLC_LPC32XX
- 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
- 8.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/mtd
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 3.7 | 5.10.261 | 307e4f4c1d4e |
| 3.7 | 5.15.212 | c367af37ce72 |
| 3.7 | 6.1.178 | 623c4d8e740d |
| 3.7 | 6.6.145 | bd4a622786f9 |
| 3.7 | 6.12.97 | 8f5c3ee53a5d |
| 3.7 | 6.18.40 | cf7258f57d18 |
| 3.7 | 7.1.5 | cb2031f8b226 |
| 3.7 | 7.2 | 17a8ce84964f |
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 lpc32xx SLC NAND driver is only exercised through local kernel storage entry points—read/write/ioctl on /dev/mtd* or mtdblock, VFS access to flash-backed mounts (UBIFS/JFFS2/squashfs), or in-kernel mtd_read/mtd_write callers—not via any network packet or remote protocol handler.
- AC:LAttack complexity, low
- An attacker with flash access can repeatedly issue MTD or filesystem read/write operations to stress the NAND controller and DMA engine, hunting for completion timeouts; they control I/O timing and can retry without depending on rare victim-only state beyond issuing local storage traffic.
- PR:LPrivileges required, low
- Unprivileged local users on typical LPC32xx embedded systems can reach the vulnerable DMA path by reading executables or files from flash-backed root filesystems or world-readable mtdblock nodes; root-only /dev/mtd access is not required for the read path through lpc32xx_nand_read_page_syndrome.
- UI:NUser interaction, none
- Exploitation requires only attacker-initiated storage I/O against the NAND-backed device or mounted filesystem; no victim interaction such as plugging media, approving dialogs, or opening attacker-supplied content is needed.
- S:CScope, changed
- On DMA timeout the driver unmaps the scatterlist while in-flight DMA may continue, allowing the NAND DMA engine to access physical pages reused for unrelated kernel objects—crossing the intended DMA buffer security boundary of the driver.
- C:HConfidentiality impact, high
- Continued DEV_TO_MEM DMA after dma_unmap_sg can write into repurposed physical pages and leak their prior contents upward; falsely reporting success also returns incomplete or attacker-influenced NAND page data, and post-unmap DMA enables arbitrary kernel memory disclosure via controlled page reuse.
- I:HIntegrity impact, high
- In-flight DMA after dma_unmap_sg provides a DMA-after-free style write primitive that can corrupt adjacent kernel heap or stack objects, enabling control-flow hijacking and privilege escalation beyond the intended NAND transfer buffer.
- A:HAvailability impact, high
- DMA-after-unmap corruption commonly provokes kernel oops, panic, or hang; falsely successful timed-out writes can also corrupt flash contents or filesystem metadata on industrial LPC32xx appliances, causing sustained denial of service or device bricking.