Out-of-bounds write in it51xxx I2C target FIFO ISR on oversized write transaction

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-14986
StatePUBLISHED
Assignerzephyr
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-14 23:17:15 UTC
Updated2026-09-18 19:11:57 UTC
DescriptionThe ITE it51xxx I2C driver, when operating as an I2C target (slave) in buffer mode (CONFIG_I2C_TARGET + CONFIG_I2C_TARGET_BUFFER_MODE), copies host-supplied write data into the fixed-size data->target_in_buffer inside its target FIFO interrupt handler target_i2c_isr_fifo() in drivers/i2c/i2c_ite_it51xxx.c. The copy loop stores to target_in_buffer[i + data->w_index] and only checks data->w_index against sizeof(data->target_in_buffer) after the write has already completed, so the bounds check cannot prevent the overflow. The running index data->w_index accumulates count bytes on every FIFO-fill interrupt of an ongoing transaction and is reset to zero only on a STOP or timeout condition. An I2C host that streams a single write transaction longer than the buffer (default CONFIG_I2C_TARGET_IT51XXX_MAX_BUF_SIZE = 256 bytes) drives data->w_index past the end of the buffer, and each subsequent host byte is written out of bounds into the adjacent data->target_out_buffer and following static device data. The trigger is a malicious or misbehaving I2C master on the same bus (for example a compromised application processor or a rogue device on an exposed I2C bus); no software privilege on the victim is required and the handler runs in the target's kernel/firmware context. Because both the written values and the overflow length are attacker-controlled, this is an out-of-bounds write that can crash the controller or be shaped toward code execution. The fix adds a pre-write bounds check in target_i2c_fifo_read_to_buf() that aborts and resets the FIFO before any out-of-bounds store.

Risk And Classification

Primary CVSS: v3.1 6.8 MEDIUM from [email protected]

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001820000 probability, percentile 0.080600000 (date 2026-09-21)

Problem Types: CWE-787 | CWE-787 bounds

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.8MEDIUMCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNACVSS6.8MEDIUMCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Physical
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Zephyrproject Zephyr affected 4.2.0 4.4.2 semver Not specified

References

ReferenceSourceLinkTags
github.com/zephyrproject-rtos/zephyr/commit/eac92173cf13bba4e6c6eea3460e... [email protected] github.com
github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-jmjj-w736-... [email protected] github.com
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