CVE-2026-98959
Description
A flaw was found in the Linux kernel's Btrfs file system. A local user can cause a Denial of Service (DoS) and file system corruption by replacing an extended attribute (xattr) with a value of a different size on files where multiple attributes share the same directory item. Because the kernel fails to fully initialize the newly relocated attribute item, subsequent writeback operations fail consistency checks and force a transaction abort.
Statement
This vulnerability is rated as Moderate severity because exploitation is restricted to local authenticated users with write permissions on an active Btrfs volume, limiting the blast radius to localized denial of service and filesystem corruption rather than arbitrary code execution or privilege escalation. Additionally, Btrfs is not configured as the default filesystem on Red Hat Enterprise Linux and has been deprecated or removed in recent major versions, meaning standard installations do not expose this attack surface unless non-standard storage configurations are specifically deployed.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 9.8 |
| Attack Vector | Local | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory; Read Application Data
When reusing a resource such as memory or a program variable, the original contents may not have been cleared before it is sent to an untrusted party.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Instability
The uninitialized resource may contain values that cause program flow to change in ways that the programmer did not intend, possibly leading to a crash.
Other
Technical Impact: Unexpected State; Varies by Context
The consequences vary depending on the type of resource and how it is used within the product.
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