CVE-2026-10678: The MCTP-over-I2C+GPIO target binding in Zephyr (subsys/pmci/mctp/mctp_i2c_gpio_target.c) processes pseudo-reg

Q: How do I fix CVE-2026-10678?

zephyr: upgrade to newer than 4.4.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-10678 being exploited?

CVE-2026-10678 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-10678 affect?

CVE-2026-10678 affects zephyr. Severity is high (CVSS 8.1). The MCTP-over-I2C+GPIO target binding in Zephyr (subsys/pmci/mctp/mctp_i2c_gpio_target.c) processes pseudo-register writes from an I2C bus master byte-by-byte in mctp_i2c_gpio_target_write_received() without validating the order or the rece

Routine

HIGH 8.1UPGRADE

CVE-2026-10678 is a high-severity flaw (CVSS 8.1) affecting zephyr. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The MCTP-over-I2C+GPIO target binding in Zephyr (subsys/pmci/mctp/mctp_i2c_gpio_target.c) processes pseudo-register writes from an I2C bus master byte-by-byte in mctp_i2c_gpio_target_write_received() without validating the order or the receive buffer. In the affected versions the MCTP_I2C_GPIO_RX_MSG_ADDR (data) handler dereferences and writes through b->rx_pkt without checking that the receive buffer was allocated: a controller that selects the

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-476, CWE-787
Published	2026-07-21
Last modified	2026-10-24

Publisher (CNA): Zephyr Project · Vendor: zephyrproject

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-21 22:17 UTCPublished CVE record published
2026-10-24 19:10 UTCUpdated Record last modified

zephyrproject zephyr UPGRADE

Affected: >= 4.3.0 and <= 4.4.1

Fixed in: newer than 4.4.1

Safe to downgrade to: a release before 4.3.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-10678?

zephyr: upgrade to newer than 4.4.1. Exact commands for each OS are on this page.

Is CVE-2026-10678 being exploited?

CVE-2026-10678 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-10678 affect?

CVE-2026-10678 affects zephyr. Severity is high (CVSS 8.1). The MCTP-over-I2C+GPIO target binding in Zephyr (subsys/pmci/mctp/mctp_i2c_gpio_target.c) processes pseudo-register writes from an I2C bus master byte-by-byte in mctp_i2c_gpio_target_write_received() without validating the order or the rece

How urgent is CVE-2026-10678?

Priority 36/100. High severity

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References

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