# CVE-2026-10683: Zephyr OS Synopsys DesignWare I2C driver denial of service

Source: https://junglewise.ai/threats/cve-2026-10683-zephyr-os-synopsys-designware-i2c-driver-denial-of-service  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-27. Updated: 2026-07-27  
License: CC BY 4.0 with a link back

CVE-2026-10683 · Severity: low · CVSS 2.4 · Published 2026-07-27

A vulnerability in the Zephyr operating system's I2C driver can allow a hardware device on the same physical bus to disable communication with the affected system. By sending specific, valid I2C sequences or causing minor electrical glitches, an attacker can cause the driver to enter a permanent 'stuck' state. This results in a denial of service where the system can no longer receive data from the I2C bus until it is manually reset.

Technologies: [Zephyr Project Zephyr OS](https://junglewise.ai/threats/technologies/zephyr-os). Vendors: [Zephyr Project](https://junglewise.ai/threats/vendors/zephyr-project).

## Quick answers

**Is CVE-2026-10683 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-10683 being exploited in the wild.

**How severe is CVE-2026-10683?** Low severity, with a CVSS score of 2.4, published 27 July 2026.

**Which products and versions are affected?** Zephyr Project Zephyr OS >= 4.0.0, < 4.5.0.

**Is there a fix for CVE-2026-10683?** A patch was published on 2026-07-27. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-10683 attacked?** It is attacked with physical access, in an operating system.

**Am I affected by CVE-2026-10683?** Check whether you run Zephyr Project Zephyr OS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A logic error exists in the Synopsys DesignWare I2C driver (drivers/i2c/i2c_dw.c) when operating in target/slave mode. The `rx_full` interrupt handler gates the `write_requested()` callback based on the driver state, but the state is only reset to `READY` upon receiving a `STOP` interrupt. Because the `START_DET` interrupt was omitted from the enabled interrupt mask in `i2c_dw_slave_register()`, the driver cannot recover its state if a `STOP` interrupt is missed or if a master issues a legal 'WRITE-repeated-START-WRITE' sequence. An attacker with physical access to the I2C bus can exploit this to permanently wedge the driver in a `CMD_SEND` state, preventing further write transactions. The issue is resolved by unmasking the `START_DET` interrupt to ensure state resets on every bus (re)START.

## Affected products

- Zephyr Project Zephyr OS >= 4.0.0, < 4.5.0

## Timeline

- 2026-07-27: disclosed
- 2026-07-27: advisory
- 2026-07-27: patched

## References

- [https://github.com/zephyrproject-rtos/zephyr](https://github.com/zephyrproject-rtos/zephyr)
- [https://github.com/zephyrproject-rtos/zephyr/commit/06e2053efe0e324d71cc29cdd95160fff643730a](https://github.com/zephyrproject-rtos/zephyr/commit/06e2053efe0e324d71cc29cdd95160fff643730a)
- [https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-fj9c-r5qw-3639](https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-fj9c-r5qw-3639)

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