CVE-2021-47153: i2c: i801: Don't generate an interrupt on bus reset

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-03-25 · updated 2026-08-04
Weakness: CWE-125

Description

In the Linux kernel, the following vulnerability has been resolved: i2c: i801: Don't generate an interrupt on bus reset Now that the i2c-i801 driver supports interrupts, setting the KILL bit in a attempt to recover from a timed out transaction triggers an interrupt. Unfortunately, the interrupt handler (i801_isr) is not prepared for this situation and will try to process the interrupt as if it was signaling the end of a successful transaction. In the case of a block transaction, this can result in an out-of-range memory access. This condition was reproduced several times by syzbot: https://syzkaller.appspot.com/bug?extid=ed71512d469895b5b34e https://syzkaller.appspot.com/bug?extid=8c8dedc0ba9e03f6c79e https://syzkaller.appspot.com/bug?extid=c8ff0b6d6c73d81b610e https://syzkaller.appspot.com/bug?extid=33f6c360821c399d69eb https://syzkaller.appspot.com/bug?extid=be15dc0b1933f04b043a https://syzkaller.appspot.com/bug?extid=b4d3fd1dfd53e90afd79 So disable interrupts while trying to reset the bus. Interrupts will be enabled again for the following transaction.

Affected products

Linux kernel: from 3.6 before 4.4.271; from 4.5 before 4.9.271; from 4.10 before 4.14.235; from 4.15 before 4.19.193; from 4.20 before 5.4.124; from 5.5 before 5.10.42 — fixed in 4.14.235, 4.19.193, 4.4.271, 4.9.271, 5.10.42, 5.12.9

How to fix

Upgrade to a fixed version: Linux kernel 4.14.235, 4.19.193, 4.4.271, 4.9.271. Check the vendor advisory for mitigations.

References

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