CVE-2026-80578

CVE Details

Release Date:	2026-08-26
Impact:	Low	What is this?

Description

In the Linux kernel, the following vulnerability has been resolved: fbdev: core: Fix pointer desynchronization in fb_io_read() In fb_io_read(), if copy_to_user() performs a partial copy (e.g., due to a faulty user buffer), the loop adjusts the chunk size 'c' and updates the remaining 'count'. However, the hardware 'src' pointer has already been eagerly advanced by the original chunk size. If the loop is allowed to continue, the read will resume from an incorrect, over-advanced offset. Since the remaining 'count' was only decremented by the successful bytes, this desynchronization causes the next iterations to execute more hardware reads than originally bounded, eventually leading to out-of-bounds I/O reads. Fix this by breaking out of the loop immediately upon a partial copy_to_user(). A partial copy indicates a faulty user buffer, making subsequent read attempts futile. Breaking out ensures we return the number of successfully read bytes without risking out-of-bounds hardware accesses in subsequent mismatched iterations.

See more information about CVE-2026-80578 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	3.3
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	Low
Integrity Impact:	None
Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (kernel-uek)	ELSA-2026-500374	2026-10-07