Bug 2481978 (CVE-2026-45865) - CVE-2026-45865 kernel: mctp i2c: initialise event handler read bytes
Summary: CVE-2026-45865 kernel: mctp i2c: initialise event handler read bytes
Keywords:
Status: NEW
Alias: CVE-2026-45865
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-27 15:05 UTC by OSIDB Bzimport
Modified: 2026-05-28 04:01 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-05-27 15:05:18 UTC 
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.
Comment 1 Keith Grant 2026-05-28 03:59:24 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052711-CVE-2026-45865-87b8@gregkh/T
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