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CVE-2026-92501

kernel: ext4: drain in-flight DIO before buffered write fallback

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Severity

Moderate

Red Hat Product Security

5.5

CVSS 3.1

Review impact separately from score.

Published · September 17, 2026

Updated · November 1, 2026

Description

A flaw was found in the Linux kernel's ext4 filesystem. A race condition exists during direct I/O (DIO) operations when the system falls back to buffered I/O. This unprotected timing window allows concurrent I/O operations to incorrectly invalidate cached data, leading to input/output (I/O) errors. A local user or process performing normal file operations could trigger this issue, potentially causing a Denial of Service (DoS) by making the filesystem unresponsive or corrupting data.

Statement

Red Hat has evaluated this issue as having Moderate severity because exploitation is restricted to authenticated local users and primarily leads to file write errors or denial of service, without granting elevated privileges or disclosing confidential information. The timing condition requires a specific sequence of concurrent asynchronous direct I/O and buffered fallback operations, which is rarely encountered under standard enterprise workloads on modern ext4 installations that utilize extent-based allocation. Consequently, the impact is confined to localized I/O failures for the affected processes or files rather than a complete system compromise.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

CVSS / CWE

CVSS 3.1 · 5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition