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Fencer Vulns
low 2.4

CVE-2026-10683 json

DesignWare I2C target driver can be wedged into a permanent stuck state by an on-bus master (DoS)

published 2026-07-27 3 mo ago modified 2026-11-04 5 d ago also EUVD-2026-49399

cvss
2.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

In the Synopsys DesignWare I2C driver (drivers/i2c/i2c_dw.c) operating in target/slave mode, the rx_full interrupt handler gates the write_requested() callback on dw->state != CMD_SEND, and dw->state is only reset to READY on a STOP interrupt. The START_DET interrupt, whose handler in i2c_dw_slave_read_clear_intr_bits() would reset the state on every (re)START, was never added to the enabled interrupt mask in i2c_dw_slave_register(), so that recovery path was dead code.

As a result, if the STOP interrupt is lost (bus glitch/reset, or a concurrent master driving STOP) or the bus master issues a legal WRITE-repeated-START-WRITE sequence with the same direction, the driver remains in CMD_SEND permanently and never invokes write_requested() again for the life of the target.

An I2C master on the same physical bus can deliberately trigger this, causing the I2C target function to malfunction for all subsequent write transactions and desynchronizing consumer framing state (e.g. MCTP-over-I2C), a recoverable-by-reset denial of service of the target peripheral.

The fix unmasks START_DET so the state is reset at every bus (re)START. Impact is availability-only over a local board-level bus; no memory corruption results in the in-tree consumer, whose per-byte buffer write is independently bounds-checked.

Patch / fix

  • zephyrproject zephyr 4.3.2, 4.4.2

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-fj9c-r5qw-3639 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 2.4 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 4.6 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • zephyrproject zephyr

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.