CyberRota Analysis
AI-GeneratedThe vulnerability affects the Synopsys DesignWare I2C driver operating in target/slave mode, where a failure to handle certain interrupts can lead to the driver remaining in a permanent CMD_SEND state. This condition can be exploited by an I2C master on the same bus, resulting in a denial of service for the target peripheral, as it will not process subsequent write transactions until reset. Organizations utilizing this driver in environments where I2C communication is critical should prioritize addressing this issue to maintain system availability.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
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.
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