CVE-2026-89748

Received Received - Intake

Linux Kernel Ring Buffer Reader Swap Exhaustion Fix

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. The current !retry test reverses both outcomes. It returns an error after a successful final replacement, leaving the link update complete but the reader bookkeeping unfinished. After a failed final replacement, it falls through and updates the head and reader pointers as though the replacement succeeded, which can corrupt the ring. Treat only a negative counter as exhaustion and return the documented -EBUSY error.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-11

Last Modified

2026-09-11

Generated

2026-09-12

AI Q&A

2026-09-12

EPSS Evaluated

N/A

NVD

CVE-2026-89748

EUVD

EUVD-2026-76660

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a flaw in the simple ring buffer reader swap function. The function uses a retry counter that starts at 8 and decrements after each failed attempt. When retry reaches zero after a successful replacement, the code incorrectly treats it as an error and returns -EBUSY. If the replacement fails, it incorrectly proceeds as if it succeeded, leading to potential ring buffer corruption.

Detection Guidance

This vulnerability is specific to the Linux kernel's tracing subsystem and does not have a direct network detection method. Detection requires checking kernel logs for errors related to ring buffer operations or tracing failures.

Impact Analysis

This vulnerability could lead to system instability or crashes due to ring buffer corruption. It may cause data loss or unpredictable behavior in applications relying on the affected kernel functionality. Systems using vulnerable Linux kernel versions could experience performance degradation or unexpected failures.

Mitigation Strategies

Apply the latest Linux kernel patches that address this issue. Monitor kernel logs for tracing-related errors and update affected systems to a patched kernel version as soon as possible.

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