# CVE-2026-80931: w1: ds28e17: reject an oversize length on an I2C block read

CVE-2026-80931 is fixed in 12 products on 1 platform, first by DEBIAN-CVE-2026-80931, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-80931
- Priority: High
- CVSS: 7.8 (Moderate)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-80931

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-default sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.90.1.150700.17.51.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-livepatch-SLE15-SP7_Update_24 sles 15.7 | 1-150700.15.3.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-source sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | linux Debian 12.15 (bookworm) | 6.1.190-1 | [DEBIAN-CVE-2026-80931](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80931.md) | Sep 23, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-80931](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80931.md) | Sep 23, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-80931](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80931.md) | Sep 23, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-80931](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80931.md) | Sep 23, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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