High [CVE-2026-64191] Reject I2C block transfers with invalid length
This high-severity Red Hat Linux advisory covers CVE-2026-64191 affecting Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 10.
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Summary
In the Linux kernel, the following vulnerability has been resolved: i2c: stub: Reject I2C block transfers with invalid length The I2C_SMBUS_I2C_BLOCK_DATA case in stub_xfer() uses data->block[0] as the transfer length.
The existing check only clamps it to avoid overrunning the chip->words[256] register array, but does not validate it against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union i2c_smbus_data.block buffer (34 bytes total). The driver is a development/test tool (CONFIG_I2C_STUB=m, not built by default) that must be loaded with a chip_addr= parameter.
Affected products named by the advisory: Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 7; and 1 more.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
- kernel-rt-0:4.18.0-553.158.1.rt7.499.el8_10
- kernel-0:4.18.0-553.158.1.el8_10
- kernel-0:5.14.0-687.42.1.el9_8
- RHSA-2026:59737
- RHSA-2026:59821
- RHSA-2026:59723
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
Mitigation
Upgrade to a fixed release: kernel-rt-0:4.18.0-553.158.1.rt7.499.el8_10, kernel-0:4.18.0-553.158.1.el8_10, kernel-0:5.14.0-687.42.1.el9_8, RHSA-2026:59737, RHSA-2026:59821, RHSA-2026:59723. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
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