# CVE-2026-80931

## Summary

- **CVE ID:** CVE-2026-80931
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 14, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:

w1: ds28e17: reject an oversize length on an I2C block read

w1_f19_i2c_master_transfer() is the master_xfer for the DS28E17 1-Wire
to I2C bridge. On an I2C_M_RECV_LEN read, it takes the length from the
device. The downstream slave puts a length byte in buf[0]. The driver
then reads that many bytes into buf[1] with w1_f19_i2c_read().

buf[0] is controlled by the device and can be 0 to 255.
w1_f19_i2c_read() only rejects a zero count. The caller buffer is
I2C_SMBUS_BLOCK_MAX + 2, so 34 bytes. A length above 32 makes the read
run past it, up to about 222 bytes out of bounds.

The SMBus core does check buf[0] against I2C_SMBUS_BLOCK_MAX. That
check runs after master_xfer returns. By then the write is already
done. i2c-algo-bit rejects an oversize length before it copies, and
returns -EPROTO.

Reject a length above I2C_SMBUS_BLOCK_MAX at both RECV_LEN sites, the
same way i2c-algo-bit does.

## Affected Products

- Linux — Linux (ebc4768ac4971eab4b570e733e47ac9dfd0e4175)
- Linux — Linux (4.15)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/cb55c5da9828f77db2a2701316949d4de1e9b773)
- [CNA](https://git.kernel.org/stable/c/ae0c79a8527044e54d81fd5a3b49ce6177633758)
- [CNA](https://git.kernel.org/stable/c/6df05f630c84a109736642362e452089886f9974)
- [CNA](https://git.kernel.org/stable/c/169ae5e65e5aaf213b6a578f6478a9fd2e523606)
- [CNA](https://git.kernel.org/stable/c/b30c021c6073559ea6851b522d8a17a524a27b4a)
- [CNA](https://git.kernel.org/stable/c/1d08877fc37e90945df38d255715bd1d6c052d46)
- [CNA](https://git.kernel.org/stable/c/bf76d61e118b7044600a65775a3bf8adc2c6823d)
- [CNA](https://git.kernel.org/stable/c/0f6496b34cc2919420f303b2aabdd9f71e084b56)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.13%
- **EPSS Percentile:** 2.9

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._