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7.8
HIGH CVSS 3.1
CVE-2026-89503
ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()
Overview
Description

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page() ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set, it can allocate a reader page with an outdated order. This isn't a big issue, the user can still re-allocate a new reader page and try again. However, what is more problematic is if the value of subbuf_order changes in the middle of ring_buffer_alloc_read_page(). In that case, bpage->order might not match the actual allocated memory. Use bpage->order for the allocation to prevent this race.

Details
INFO

Published Date :

Sept. 11, 2026, 8:19 p.m.

Last Modified :

Oct. 3, 2026, 11:17 a.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-89503 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Race condition in ring buffer sub-buffer resizing resolved by using bpage->order for allocation.
  • Update the Linux kernel.
  • Use bpage->order for buffer allocation.
  • Re-allocate reader pages if needed.
  • Retry operations if allocation fails.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-89503.

URL Resource
https://git.kernel.org/stable/c/2313ff69bd237aad264a5913907f374f958335a2
https://git.kernel.org/stable/c/2dc510957fe8fd098ab3c3147ebdf34d00cd2734
https://git.kernel.org/stable/c/53106e9262a310ef2c9a9321168c03705940c678
https://git.kernel.org/stable/c/e743527c5bfdceda1095bc0a9e596e2aebb6a9c3
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-89503 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-89503 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-89503 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-89503 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Oct. 03, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89503.json">CVE-2026-89503</a>
    Added Reference https://git.kernel.org/stable/c/2313ff69bd237aad264a5913907f374f958335a2
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Sep. 13, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Sep. 11, 2026

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page() ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set, it can allocate a reader page with an outdated order. This isn't a big issue, the user can still re-allocate a new reader page and try again. However, what is more problematic is if the value of subbuf_order changes in the middle of ring_buffer_alloc_read_page(). In that case, bpage->order might not match the actual allocated memory. Use bpage->order for the allocation to prevent this race.
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89503.json">CVE-2026-89503</a>
    Added Reference https://git.kernel.org/stable/c/2dc510957fe8fd098ab3c3147ebdf34d00cd2734
    Added Reference https://git.kernel.org/stable/c/53106e9262a310ef2c9a9321168c03705940c678
    Added Reference https://git.kernel.org/stable/c/e743527c5bfdceda1095bc0a9e596e2aebb6a9c3
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 7.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact