What’s Vulnerable › Vulnerabilities

CVE-2026-45865: mctp i2c: initialise event handler read bytes

• Severity: medium (CVSS 5.5 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: 2026-05-27 · updated 2026-06-25

Description

In the Linux kernel, the following vulnerability has been resolved: mctp i2c: initialise event handler read bytes Set a 0xff value for i2c reads of an mctp-i2c device. Otherwise reads will return "val" from the i2c bus driver. For i2c-aspeed and i2c-npcm7xx that is a stack uninitialised u8. Tested with "i2ctransfer -y 1 r10@0x34" where 0x34 is a mctp-i2c instance, now it returns all 0xff.

Affected products

• Linux kernel: from 5.18 before 6.1.165; from 6.2 before 6.6.128; from 6.7 before 6.12.75; from 6.13 before 6.18.14; from 6.19 before 6.19.4 — fixed in 6.1.165, 6.12.75, 6.18.14, 6.19.4, 6.6.128

How to fix

Upgrade to a fixed version: Linux kernel 6.1.165, 6.12.75, 6.18.14, 6.19.4. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/11f83253244060b5de5eac787f61ae3f3e559d01
• https://git.kernel.org/stable/c/1eeedb310229bfee9dd4d992e5bba33fe1378a8f
• https://git.kernel.org/stable/c/2a14e91b6d76639dac70ea170f4384c1ee3cb48d
• https://git.kernel.org/stable/c/6ff2ebfef75fbc57d937d8fbe738b967edf2d331
• https://git.kernel.org/stable/c/93e01e837e105299f1c259ef71f6e1ec4fe806e3
• https://git.kernel.org/stable/c/fa9861e5c8af7651dddfa8d490aaada17ae33b6c

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