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CVE-2026-93190
platform/chrome: cros_ec_typec: Reject out-of-bounds PD cap count
Published 2026-09-17 (31 days ago) by the Linux kernel CNA. Subsystem drivers/platform. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-93190 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-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
cros_typec_register_partner_pdos() copies the partner PDOs from the EC TYPEC_STATUS response into the fixed caps_desc.pdo[PDO_MAX_OBJECTS] array. memcpy(caps_desc.pdo, resp->source_cap_pdos, sizeof(u32) * resp->source_cap_count); ... memcpy(caps_desc.pdo, resp->sink_cap_pdos, sizeof(u32) * resp->sink_cap_count); PDO_MAX_OBJECTS is 7. source_cap_count and sink_cap_count are u8 fields from the EC. The only check is that they are not both zero. If either is larger than 7, the memcpy writes past the end of the array on the stack. A count of 255 overflows it by about 1 KB. The EC source arrays are only seven entries wide. A larger count reads past them too. The ChromeOS EC firmware caps these counts today, so a compliant setup does not hit this. The kernel should still validate these values rather than trust them. Validate the counts in cros_typec_register_partner_pdos() next to the memcpy. Skip the PDO registration if either count is above PDO_MAX_OBJECTS. The rest of cros_typec_handle_status() still runs so events are handled and cleared.
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/platform/chrome/cros_ec_typec.c
- What this is
- CHROMEOS EC USB TYPE-C DRIVERMAINTAINERS section matched on drivers/platform/chrome/cros_ec_typec.* · chrome-platform@lists.linux.dev · Maintained
- Kernel module
- cros_ec_typec
Check it on the machine
grep -wE 'CONFIG_CHROME_PLATFORMS|CONFIG_CROS_EC_TYPEC' /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 cros_ec_typecPrints 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/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le
- trixieMnot built on amd64/cloud-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/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_CHROME_PLATFORMS, CONFIG_CROS_EC_TYPEC
- 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
- 2026-09-17 (31 days 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
- 0.17%, higher than 5.7% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/platform
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.1 | 6.1.188 | 7617b210a220 |
| 6.1 | 6.6.157 | 4e37371cb4e3 |
| 6.1 | 6.12.110 | 2a7a4e45a3aa |
| 6.1 | 6.18.52 | e4728288473a |
| 6.1 | 7.2.6 | 54d6b0ee9b8b |
| 6.1 | 7.3 | a0a8cd9fc9c4 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | 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 overflowing length is the u8 source_cap_count/sink_cap_count in the EC_CMD_TYPEC_STATUS (0x0133) reply that cros_typec_handle_status() fills via cros_ec_cmd(), from cros_typec_probe()/cros_ec_typec_event() over the onboard ChromeOS EC bus. USB PD's 3-bit Number of Data Objects (PD_HEADER_CNT_MASK) cannot exceed 7, so a USB-C partner cannot supply this count.
- AC:LAttack complexity, low
- A compromised EC returns EC_CMD_USB_PD_CONTROL with PD_CTRL_RESP_ENABLED_CONNECTED so cros_typec_add_partner() runs, then TYPEC_STATUS with PD_STATUS_EVENT_SOP_DISC_DONE and source_cap_count=255. memcpy() then copies 1020 bytes into caps_desc.pdo[PDO_MAX_OBJECTS] deterministically, with no race.
- PR:NPrivileges required, none
- cros_typec_probe() and the EC_HOST_EVENT_PD_MCU notifier call cros_typec_port_update() with no Linux capability or credential check. Compromised EC firmware can advertise EC_FEATURE_TYPEC_CMD and return the malicious TYPEC_STATUS without a host account.
- UI:NUser interaction, none
- cros_typec_probe() already calls cros_typec_port_update() for each port before registering the PD notifier, so a malicious EC that reports a connected partner and SOP_DISC_DONE overflows at boot. No victim need plug a cable or open a device.
- S:UScope, unchanged
- The smash is the kernel stack of cros_typec_register_partner_pdos() in the same host OS that runs the ChromeOS EC Type-C driver. This is ordinary kernel memory corruption, not a VM escape or IOMMU bypass.
- C:HConfidentiality impact, high
- memcpy() of source_cap_count*sizeof(u32) from resp->source_cap_pdos (only seven u32s) into caps_desc.pdo[7] both over-reads the TYPEC_STATUS stack object by up to ~1KB and overflows later stack, which that smash can turn into an arbitrary-read primitive.
- I:HIntegrity impact, high
- A source_cap_count of 255 writes about 1KB past the 28-byte caps_desc.pdo array on the stack of cros_typec_register_partner_pdos(), overwriting saved registers and the return address for control-flow hijack and an arbitrary write.
- A:HAvailability impact, high
- Smashing the stack frame of cros_typec_register_partner_pdos() while handling EC_CMD_TYPEC_STATUS oopses or panics the kernel on Chrome OS EC systems, a full availability loss.