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CVE-2026-64333
USB: serial: digi_acceleport: fix write buffer corruption
Published 2026-07-25 (3 months ago) by the Linux kernel CNA. Subsystem drivers/usb. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-64333 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-4720-1 · 2026-08-05 · text | 6.1.180-1 | Update the kernel and reboot. DLA-4720-1 shipped the fix on 2026-08-05, in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.96-1 | Update the kernel and reboot. Fixed in 6.12.96-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4724-1 · 2026-08-07 · text | 6.12.100-1~deb12u1 | Update the kernel and reboot. DLA-4724-1 shipped the fix on 2026-08-07, in 6.12.100-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The digi_write_inb_command() is supposed to wait for the write urb to become available or return an error, but instead it updates the transfer buffer and tries to resubmit the urb on timeout. To make things worse, for commands like break control where no timeout is used, the driver would corrupt the urb immediately due to a broken jiffies comparison (on 32-bit machines this takes five minutes of uptime to trigger due to INITIAL_JIFFIES). Fix this by adding the missing return on timeout and waiting indefinitely when no timeout has been specified as intended. This issue was (sort of) flagged by Sashiko when reviewing an unrelated change to the driver.
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/usb/serial/digi_acceleport.c
- What this is
- USB SERIAL SUBSYSTEMMAINTAINERS section matched on drivers/usb/serial/ · linux-usb@vger.kernel.org · Maintained
- Kernel module
- digi_acceleport
Check it on the machine
grep -wE 'CONFIG_OF|CONFIG_PCI|CONFIG_USB|CONFIG_USB_GADGET|CONFIG_USB_PHY|CONFIG_USB_SERIAL|CONFIG_USB_SERIAL_DIGI_ACCELEPORT|CONFIG_USB_SUPPORT' /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.
lsmod | grep -w digi_acceleportPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, i386/686, i386/686-pae, i386/rt/686-pae, ppc64el/powerpc64le
- trixieMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, armel/rpi, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- forky, sidMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt-amd64, arm64/cloud-arm64, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_OF, CONFIG_PCI, CONFIG_USB, CONFIG_USB_GADGET, CONFIG_USB_PHY, CONFIG_USB_SERIAL, CONFIG_USB_SERIAL_DIGI_ACCELEPORT, CONFIG_USB_SUPPORT
- 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
- 2026-07-25 (3 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.17%, higher than 5.8% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/usb
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 2.6.12 | 5.10.261 | 5d9dc88bdf88 |
| 2.6.12 | 5.15.212 | 2f296974acc2 |
| 2.6.12 | 6.1.178 | e60e4873e917 |
| 2.6.12 | 6.6.145 | 699dfb691750 |
| 2.6.12 | 6.12.96 | a274b3794fe1 |
| 2.6.12 | 6.18.39 | 1243f1207900 |
| 2.6.12 | 7.1.4 | a3a13fdc5310 |
| 2.6.12 | 7.2 | 24ca1fea8f27 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4724-1 | 2026-08-07 | bookworm 6.12.100-1~deb12u1 | tracker |
| DLA-4723-1 | 2026-08-07 | bullseye 6.1.180-1~deb11u1 | tracker |
| DLA-4720-1 | 2026-08-05 | bookworm 6.1.180-1 | tracker |
| DLA-4717-1 | 2026-08-05 | bullseye 5.10.262-1 | 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 vulnerability is reached locally through write() followed by ioctl(TIOCCBRK) on an open Digi ttyUSB device; the attached adapter is a platform prerequisite rather than the attack entry point.
- AC:LAttack complexity, low
- The attacker controls both URB submission and the competing break command and can repeat the sequence or stall transmission to widen the window. No uncontrollable race or memory layout is required.
- PR:LPrivileges required, low
- No capability check exists in the ioctl path; the attacker only needs ordinary user-level permission to access the tty device node.
- UI:NUser interaction, none
- The attacker can open, write to, and issue the ioctl without another user performing any action.
- S:UScope, unchanged
- Compromise remains within the host kernel's security authority and is a standard local kernel privilege escalation rather than a VM, IOMMU, or distinct-scope escape.
- C:HConfidentiality impact, high
- On controller-local-memory HCDs, the changed length can make USB completion restore the transfer-buffer pointer from attacker-controlled payload bytes. The resulting kernel-write and code-execution primitive can expose arbitrary kernel memory.
- I:HIntegrity impact, high
- A subsequent tty write dereferences the attacker-selected transfer-buffer pointer, providing an attacker-directed kernel overwrite with largely controlled contents. This can corrupt control data and plausibly achieve kernel code execution.
- A:HAvailability impact, high
- The corrupted kernel pointer can immediately cause an oops or panic, while exploitation of the arbitrary overwrite can crash or hang the entire kernel.