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CVE-2026-63959
usb: typec: tcpm/tcpci_maxim: validate header NDO against RX_BYTE_CNT
Published 2026-07-19 (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-2026-63959 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
A broken/malicious port can transmit a CRC-valid frame whose header advertises up to seven data objects but whose body carries fewer than that. Check for this, and rightfully reject the message, instead of reading from uninitialized stack memory.
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/typec/tcpm/tcpci_maxim_core.c
- What this is
- USB TYPEC CLASSMAINTAINERS section matched on drivers/usb/typec/ · linux-usb@vger.kernel.org · Maintained
- Kernel module
- tcpci_maxim
Check it on the machine
grep -wE 'CONFIG_OF|CONFIG_PCI|CONFIG_TYPEC|CONFIG_TYPEC_TCPCI_MAXIM|CONFIG_TYPEC_TCPM|CONFIG_USB|CONFIG_USB_GADGET|CONFIG_USB_PHY|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 tcpci_maximPrints 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. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookworm?
- trixieMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- ?
- not established - no Makefile entry for the affected file
- M
- a module where it is built at all; some flavours do not build it
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_OF, CONFIG_PCI, CONFIG_TYPEC, CONFIG_TYPEC_TCPCI_MAXIM, CONFIG_TYPEC_TCPM, CONFIG_USB, CONFIG_USB_GADGET, CONFIG_USB_PHY, 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
- 2026-07-19 (3 months ago)source
- CVSS
- no vector published, unrated
- Attack vector
- not published
- EPSS
- 0.21%, higher than 9.9% 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 |
|---|---|---|
| 5.10 | 6.6.143 | 0af00f1459f5 |
| 5.10 | 6.12.93 | dc17721d42e6 |
| 5.10 | 6.18.35 | 9b496e3371c0 |
| 5.10 | 7.0.12 | c4ab8e2d4432 |
| 5.10 | 7.1 | aa2f716327be |
Why the CNA scored it this way
The kernel CNA published no CVSS vector and no reasoning for CVE-2026-63959, which is why it is shown as unrated rather than given an invented score. 6,405 of the 20,413 CVEs here carry reasoning; this is not one of them.