CVE-2026-45865 PUBLISHED

mctp i2c: initialise event handler read bytes

Assigner: Linux
Reserved: 13.05.2026 Published: 27.05.2026 Updated: 27.05.2026

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.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from f5b8abf9fc3dacd7529d363e26fe8230935d65f8 to 93e01e837e105299f1c259ef71f6e1ec4fe806e3 (excl.)
  • affected from f5b8abf9fc3dacd7529d363e26fe8230935d65f8 to 11f83253244060b5de5eac787f61ae3f3e559d01 (excl.)
  • affected from f5b8abf9fc3dacd7529d363e26fe8230935d65f8 to fa9861e5c8af7651dddfa8d490aaada17ae33b6c (excl.)
  • affected from f5b8abf9fc3dacd7529d363e26fe8230935d65f8 to 6ff2ebfef75fbc57d937d8fbe738b967edf2d331 (excl.)
  • affected from f5b8abf9fc3dacd7529d363e26fe8230935d65f8 to 1eeedb310229bfee9dd4d992e5bba33fe1378a8f (excl.)
  • affected from f5b8abf9fc3dacd7529d363e26fe8230935d65f8 to 2a14e91b6d76639dac70ea170f4384c1ee3cb48d (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 5.18 is affected
  • unaffected from 0 to 5.18 (excl.)
  • unaffected from 6.1.165 to 6.1.* (incl.)
  • unaffected from 6.6.128 to 6.6.* (incl.)
  • unaffected from 6.12.75 to 6.12.* (incl.)
  • unaffected from 6.18.14 to 6.18.* (incl.)
  • unaffected from 6.19.4 to 6.19.* (incl.)
  • unaffected from 7.0 to * (incl.)

References